1200 MS Points seems like a rip off. Even half that price would be a stretch to call a "deal". I passed on this, as the game is already dated, and cost me less than $20. The DLC sale going on right now does seem like a bargain though.
Thanks for the comments...I decided to go ahead and get it since I'm having so much fun with ME2. This is the first game I've ever done more than once (about to finish the second play-through as an engineer, and I'll probably do one more as an Adept or
Mine came with it so I can't say. I do know that having played the game through a few times it is worth it for me to have everything I can for the game. It would all depend on how much you enjoy the game and how much more you want from it.
I say start without it and if you enjoy it and want more from it then go for it. The way I look at DLC if you're having to debate the cost of it then maybe your funds aren't up enough to be buying such things so just know that the out of the box content
is more than enough to enjoy.