I bought Bulletwitch (360) for the boobs. I beat it twice because it was fun.....in 2007.
Earth Defense Force (360) has to be the most technically inferior game (for it's time) that I've ever loved. It's great fun.
Lego Indiana Jones (360). I got it for free and didn't want to play anything else until I beat it.
My kid picked out The Simpsons Game (360) when I told her I wanted a game we could play together. It was awesome, and one of my favorite co-op experiences in recent history.
The Maw (XBLA) rounds out the list. Very well made, despite being pretty short. Once again, my kid chose wisely.
Everything else, with a few exceptions, have been as good as or worse than I'd expected. It's awesome to be pleasantly surprised from time to time.
