Yup go with the dlc first, then American Nightmare if you want more. The dlc gives you more insight into AW. AN is a separate game with a different story. Plenty of new enemies and weapons. Pretty fun. The only thing I didn't like is that you play each
level multiple times. The new horde mode, “Fight 'til Dawn,” is kind of fun too.
More than likely American Nightmare will be on sale this summer at one point, while I loved Alan Wake, I wasn't overly impressed with the two expansion packs, but they were not awful, I guess I was expecting more. The Signal did come free with early copies
of Alan Wake, so I should not complain, but The Writer wasn't as good as I was hoping for.
I did download the demo for American Nightmare and I enjoyed it, and the subtle changes that came with it. I plan on waiting until it goes on sale at half-off before I purchase, mainly because I don't have much free time for gaming right now. I do hope Alan
Wake 2 is in the works and this time be a true launch title for the next generation system.
I say go with the DLC first, which I also think is on sale. Just a note, one of those DLC comes free with a new purchase. Considering you can typically get a new copy for under $10, that's a really nice way to go.
The Alan Wake DLC is a must own. It gave me much more closure after i finished the two DLC and not to mention they were awesome. Not to take anything away from American Nightmare it too is a must own, but you can't go wrong with the DLC first.
I have not played American Nightmare yet, so I cannot comment on it, but I have played "The Signal" and "The Writer".
Both of those DLC packs together serve as a sort of epilogue to the end of the game Alan Wake. In all honesty, they do not move the story forward or give you that much-wanted conclusion, but it does give you a healthy dose of combat and environmental challenges.
"The signal" serves as the first half of the epilogue and "The Writer" serves as the other half. At the end of "The Writer", you are basically right back where you started- at the end of the main Alan Wake game. The DLC does not move the story forward in
any significant way (in fact, it actually adds more questions to the story, if anything), but it does provide you with significant gameplay challenges scattered around nightmarish environments.
So, basically, if you want to keep playing more Alan Wake regardless of story, then the DLC is for you. If you want to find out what happens at the end of the game, then the DLC isn't going to give you any answers.