Hooray for kickbacks. Now what do I buy?

About a week ago, I sat through a sales pitch disguised as a marketing research study for a new software tool that will be hitting the applicant tracking market in the next couple months. Normally I would just blow off something like that, but it came with the incentive of a $100 Visa gift card. Told my VP about it (in case accepting gifts from vendors is taboo) and his response was "fuck it, go buy beer with it or something."

The gift card just arrived and while I could be responsible and use it to pay a bill, practicality is zero fun. So I've got this $100 burning a hole in my pocket and not sure what to do with it. I will use part of it to pick up some supplies for a stag party I'm going to tomorrow but I may as well pick up a game with the rest of it. But I'm completely undecided and looking for feedback. The options:

Mafia II - This is probably at the top of my list. I love sandbox games, and I had a lot of fun with the original Mafia. The reviews have been mixed, however, and I'm afraid of another horribly repetitive game like Godfather.

Crackdown 2 - I loved the first game and kick myself in the ass for trading it. I've heard that the sequel is very, very close to the original - more like Crackdown 1.5 than a real sequel - and don't know if it's worth the entire cost when I can just go re-buy the original for a third of the cost.

Wait two weeks for Dead Rising 2 - There's no question in my mind that I'll be getting this game. But I'm irresponsible and I want to spend the money now, dammit.

Reach - If you're a hardcore Halo player, you may want to stop reading. I could never get into Halo. Played the first one years ago, and I played through about half of the H3 campaign and a bit of multiplayer. In my opinion, the game is far from suck but it just never really held my interests. Obviously Reach is the new big thing, I'll have no difficulty finding people to play with, and the reviews are fantastic.

Something else that I'm missing - New games are always coming out and my last new game purchase was Red Dead Redemption, and Bad Company 2 before that (unless you count APB, which is no longer playable). I haven't been lurking on the site as much as in the past so I may have completely overlooked something great.

I have other games I haven't finished yet, and barely any time to play them, but I'm in the mood to grab something. Recommendations? Any feedback on the above?