Borderlands
So there are two ways to play Borderlands, solo and co-op. Thus far I've only been in the wastelands with friends, and it is a total blast. This is the new Diablo II - with shooting instead of spellcasting. Color-coded loot spills out of boss monsters as their bloody gibs explode into the air. Vicious dog-monsters spit projectile acid. Extra-tough monsters earn the nominal prefix "Badass." There are midgets with shotguns.
I'd love to play the game by myself, too, so I can actually see the exposition and understand what the fuck is wrong with this place. Regardless, co-op is a ton of fun.
Progress: Level 14 Siren