I've got an 800 microsoft points code, and I don't really want it, so I'm looking to sell it. I've done trades on /r/steamgameswap before, that's pretty much all my credibility.
My favorite game of 2012 is actually the mod Black Mesa Source. After all this waiting it finally released and it was the best mod I've ever played. That or Half Life, but that game is pretty old, so I wouldn't count it.
Honestly, this game is pretty good for free, I got it during the reddit giveaway and it's one of 2 indie games that I still play, the other being Binding of Isaac. Definitely a decent game.
One thing I thought was that if you get 3 map packs in the limited edition, and halo has always had 10$ map packs, you're paying 90 dollars for the game and 3 map packs, and then an extra 10 for the other stuff...so the microsoft store was best because you can just buy mspoints with the giftcard...