Let's see.
Action - Bayonetta - Check out the demo first and see how you like it, Alan Wake - one of my favorite games this year with a compelling storyline
Adventure: Assassin's Creed II (you might have played this one already, I'm not sure)
WRPG: Fable II, Mass Effect 1 and 2, Oblivion, Fallout 3, Dragon Age - some of my favorites this gen and you can get lost in each of these games if you aren't careful
JRPG: Tales of Vesperia - lovely cast of characters and an interesting story, Lost Odyssey - nice story, soundtrack, and some fun characters here as well...you can also spend quite a bit of time on each of these
themanwithnoname's law: As an America's sales or NPD thread grows longer, the probabilty of the comment "America = World" [sarcasticly] being made approaches 1.
