Story: Stalker Series. (SoC, CoP) I like the weird crazyness that the Zone offers, and the story behind it. Also, the bad endings for SoC made me frowney faec.
Multiplayer: Left 4 Dead Series and Dystopia. I like very team-work oriented games. If your team fails for any reason, or you have one person who doesn't know what their doing. Your just going to outright fail. Your only as good as your team, and if I get someone who isn't top notch at the game on my side, It's okay. I'm not an asshole who bitches out people who aren't professional gamers.
What can I say? I like odd games a lot too.