Just picked this up and have some questions...

Awakening is expensive, I believe, but it's actually more of an expansion than a DLC. It was originally released in stores with its own slipcase. Most review sites estimate it will take you about 15 hours to complete Awakening (I can't say that for certain), compared to say, a 1-3 hour DLC chapter. More abilities, new mechanics, more characters, etc.

So is the DLC worth it to buy?  If I were to buy all the DLC it would cost more than what I bought the game for haha.

I'm not sure. I bought the Ultimate edition of the game which included all the DLC from the start. At this point, I haven't played all of the DLC. I can give you my opinions on what I have played.

THE STONE PRISONER - This will give you Shale, a stone golem companion. In terms of other content, there are a few decent weapons and pieces of armor (I'm a big fan of the Helm of Honnleath), and two relatively short but additional sections of the game that you can play through: Honnleath Village and Cadash Thaig (part of the Orzammar Deep Roads). Shale will interact with you and the other companions just like any other member of your team, and her presence with you can give you more scenes and more story when you finally locate Caridan in the Deep Roads. Is it worth it? I'd say yes, especially if you're planning on playing the game more than once. The party feels more complete with Shale present, and I love some of her banter with the other members of the party.

RETURN TO OSTAGAR - Essentially one very long fight between medium level Darkspawn and your team at Ostagar set after the Battle of Ostagar was lost. You get some interesting equipment here, such as Cailan's Armor and weapons, as well as Duncan's Sword and Dagger, but there isn't any real story here, even less if you don't bring Wynne and Alistair with you. You come to Ostagar, you kill a bunch of Darkspawn, you recover some lost weaponry, and if you're the sentimental type, you can give Cailan a proper funeral.  Is it worth it? Not especially, no, unless you're interested in the equipment or enough of a fan of the story that you'd like the opportunity to go back to Ostagar. I like it because Duncan's Sword is a good weapon against Darkspawn and because I always make Alistair use Cailan's armor, but I know that's not reason enough for everyone.

WARDEN'S KEEP - When everything is said and done, you get a storage chest where you can stash additional supplies (this can also improve the quality of some gear if you get it when you're low level and retrieve it when you're high level), the Warden Commander's armor, a good staff for a mage who uses cold damage (Morrigan if you are not a mage yourself), two new vendors, two optional abilities, and the opportunity to obtain Starfang, arguably the best sword in the game. You also get some backstory on Sophia Dryden, the Warden Commander during the era when the Wardens were exiled from Ferelden for rebelling against the king. The story isn't meaty, but it is interesting if you want to know more about the Wardens previous to you. Is it worth it? I'd say yes.

LELIANA'S SONG - If you're not a fan of Leliana, there is no reason to get this. It contradicts the telling of Marjolaine's story from Origins, which Leliana justifies as "the tale changes depending on who the audience is." Which means what you're playing through now might be the lie, or what she tells your Warden in Origins might be the lie, or perhaps the truth is some combination of them. Or perhaps neither of them. It's played separately from the main campaign and you get a good suit of light armor that you can use in Origins, but I doubt too many people replay this after completing it the first time. I'm a big fan of Leliana, and I can't see myself replaying it more than once.

I'm working through AWAKENING at the moment, and I'm not far enough into it to give an objective opinion on it. I have yet to play GOLEMS OF AMGARREK, WITCH HUNT, or DARKSPAWN CHRONICLES.

I've played Golems of Amgarrek.  It was pretty short, but fun and challenging.  The ending is a bit obvious, but the combat is very good.

Witch Hunt is also good.  It is a bit more of a story and less a series of fights.  However, most of the people I know who have played it said that they wish the story was done differently.  I thought it was fine.  If you're a fan of Morrigan, you should really play this one.

Awakening was good: very long for DLC.  It introduces some characters and themes for DAII, which is why I played it.  If you plan to play DAII again, and want some more specific dialog with Anders (or, to better understand his character), the you should absolutely play Awakening.  If you're a fan of the way Origins plays, then you should play the other DLC because you'll like 'em.

I haven't played any of the other DLC.

Having now played Awakening, I can't recommend it. I understand it's a bit of bridge between DA and DA2 and introduces some characters that will be present in DA2, but the story is sub-standard and the quests are uninteresting. That's my opinion, mind you. I'm sure others thoroughly enjoyed it.

I personally have all the DLC and I'd say if you want the whole story to Dragon Age: Origins, get all of them as they do complete the story.

Warden's Keep will grant players access to Soldier's Peak, two new talents and spells per class from the Power of Blood school, two new achievements, and items. In addition, Warden's Keep will include two new merchants and a Party Storage Chest that allows the player to store additional inventory.

Playtime added: About 1 to 2 hours.

The Stone Prisoner refers to the titular character of this downloadable content, Shale. In addition, the DLC also grants player access to the village of Honnleath, the abandoned dwarven Cadash Thaig, two new achievements, and crystals which act as armor and weapons for Shale.

Playtime added: About 2 to 3 hours

Return to Ostagar, this downloadable content features the return of the Warden to Ostagar. There, the Warden will discover King Cailan's armor, Duncan's weapons and the motivation behind Loghain's betrayal. In addition, Return to Ostagar will also grant the player a second chance at recruiting Dog, and one new achievement.

Playtime added: About 1 to 2 hours.

Feastday Gifts: Ten unique Feastday gifts, one for each companion (only available in Origins).

Feastday Pranks: Ten unique feastday pranks, one for each companion (only available in Origins).

Both the Gifts and Pranks have specific items for each companions, some of which are useful (Sten's Butterfly Sword) while others not so (Zevran's Chastity Belt). Use Morrigan's 'Alistair Doll' with said Grey Warden in your party for some amusing interaction. There are also items, available at Bodahn's merchant shop at your camp, that will affect your characters feelings towards the Warden. Some increase their feelings of affection by 5-10 points, while other decrease by the same amount.

The Darkspawn Chronicles features a look at an alternate history: what if your character had died in the Joining ceremony, and the Grey Wardens marched under Alistair's command instead? The content is a standalone adventure in which you command genlocks, hurlocks, shrieks, and even the mighty ogres. Includes a unique reward called Blightblood that transfers into your Awakening and Origins campaigns upon completing the DLC. There are three new achievements.

Playtime added: About 1 to 2 hours.

Leliana's Song: A standalone adventure in which you play as Leliana during the mission—and betrayal—that changed her forever. It is years before the Blight, and Leliana is a young bard whose curiosities run more to passion than to the Chant of Light. Her mentor, Marjolaine, is determined to inflict the Orlesian game of intrigue on Ferelden, and Leliana is eager to please. It is a time of adventure and excitement. And it cannot last. Includes a unique reward called Battledress of the Provocateur that transfers into your Awakening and Origins campaigns upon completing the DLC. There are three new achievements.

Playtime added: About 2 to 3 hours.

The Golems of Amgurrak: The Warden has come to Orzammar at the request of Jerrik Dace. Jerrik’s brother, Brogan led an expedition into the Deep Roads to find Amgarrak and the long-lost secrets of golem construction. The rediscovery of such a method would bring great wealth, power and prestige to House Dace, but the expedition has not returned and is now feared lost. Jerrik, along with his trusty bronto, Snug, will be joining the Warden in the search for his missing brother. Players will find other unexpected companions as they continue on the journey and will need all the help that they can get. There are three new achievements, which will each unlock a unique reward (a necklace, The High Regard of House Dace, a mace, The Reaper's Cudgel, and a belt, Sash of Forbidden Secrets) that transfers into your Origins and Awakening campaigns.

Playtime added: About 1 to 2 hours.

Witch Hunt is a downloadable content that explores the whereabouts of Morrigan, the Witch of the Wilds, who aided the Warden during the Blight. It is also the final downloadable content for Dragon Age: Origins. There are four new achievements, which each unlock a unique reward (a two-handed axe, Dragonbone Cleaver, a longbow, The Sorrows of Arlathan, a mage robe, Vestments of the Seer, and a belt, Cinch of Skillful Maneuvering) that transfers into your Origins and Awakening campaigns.

Playtime added: About 1 to 2.5 hours.

(If your character was romantically involved with Morrigan, this ties up that story arc nicely imo).

There are also three other items you can get for Dragon Age: Origins/Awakening, via playing the Dragon Age Flash game, Dragon Age Journeys.

Embri's Many Pockets is a belt available in this self-titled downloadable content. It is available for free. It can be downloaded in-game by players who have completed Chapter 1 of Dragon Age Journeys.

Stats: +5% fire resistance, +5% cold resistance, +5% electricity resistance, +5% nature resistance, +5% spirit resistance

Amulet of the War Mage is an amulet available in this self-titled downloadable content. It is available for free. It can be downloaded in-game by players who have signed up for an account in Dragon Age Journeys.

Stats: +5% fire damage, +5% cold damage, +5% electricity damage, +5% nature damage, +5% spirit damage

Helm of the Deep is a helm available in this self-titled downloadable content. It is available for free. It can be downloaded in-game by players who completed all five achievements in Dragon Age Journeys.

The achievements are to reach the gates of Orzammar, kill two monsters in a single attack, convince the Bard to join the party, defeat and ogre with all party members at full health and to defeat the hurlock emissary on any difficulty level.

Stats: +2 constitution, +10 mental resistance, +10 physical resistance

There was another, available only if you purchase a Dragon Age T-shirt online:

Mark of Vigilance is an amulet available in this self-titled downloadable content. It is available for free. It can be downloaded in-game by players who purchase a Dragon Age: Origins t-shirt from Hot Topic.

Stats: +6 defense, +2% spell resistance, +5 mental resistance

Also, for a limited time, there was available the Blood Dragon Armor:

The Blood Dragon armor set is available in this eponymous downloadable content. It is available without extra cost to players who purchased a new copy of Dragon Age: Origins. In addition, unlocking the Blood Dragon armor set in Dragon Age: Origins will also unlock it for use in Mass Effect 2. The code on the card located inside the new copy states that the download will expire April 30, 2010, but it has been used well beyond that date as of April 4, 2011.

The Blood Dragon armor set is a powerful set of silverite massive plate adorned with a crimson dragon across the left shoulder. The armor is available immediately, while the gloves, boots and helm can be purchased cheaply from Bodahn Feddic, a dwarven merchant in your party camp.

I admit, I'm a completionist of sorts, so I have all the DLC for the Xbox version. There's many more, which unfortunately are only available on the PC version, mainly armor/items/weapons etc. The story based DLC, does add to the overall story and any Dragon Age fan would get them to learn the whole story of Dragon Age: Origins. Dragon Age Awakening, like Kimieva said, it is a bridge of sorts between Dragon Age: Origins and Dragon Age II... but also it's kind of like a epilogue to Origins. While the story is less in comparison to Origins, for the final chapter of the game it does work.

Well, except that technically Witch Hunt is the epilogue to Origins. It takes place after Awakening and Golems of Amgarrak.

If nothing else, get the Feastday Gifts pack. There's a gift for Sten called the Quinari (did I spell that correctly?) Book of Prayers. Once you give it to Sten, he can use it in battle to completely revive the entire party (so log as he survives). It has no limit as to how many times it can be used. If you find a battle particularly difficult (such as a dragon), you can just control Sten, keep him safe & revive everyone as needed. It's kind of cheap tactic, but it works. Unfortunately, it can't be used in a tactic slot (so you have to be in control of Sten), but it can be mapped to a button.