Borderlands
With downloadable content streaming in now, I'd hoped that my friends would pick Borderlands up again; once you've played the game's most fun mode - that is, You And Three Friends Blowing Shit Up mode - it is difficult to go back to anything else (You're Alone In A Desert mode, or You Can't Trust These Public Game Assholes mode).
But my buddies have moved on. So, I guess I should, too.
Better than: Diablo II (great in a group)
Not as good as: BioShock (not as much, solo)
There is a Firefly reference: And it's awesome
Progress: Level 47 Berserker