Best game I hadn't really been aware of until this year: Spirit of the Century
I've written a bit about my thoughts on Spirit of the Century and FATE (the underlying system). In brief: it rocks. The GMing advice is awesome; while it is tightly focused on pulp gaming, a lot of it can be adapted to different genres. The mechanics are simple and flexible... and, most of all, they naturally promote interesting descriptions and plot twists (without being as focused on such things as a game like WuShu or Sorcerer). Also, there is an online OGL SRD for it. Check it out.
Best game I've owned for a while but hadn't played until this year: Nobilis
Angela bought me Nobilis for my birthday a while back. I would sit and look at it and think about what a pretty book it was. Then, one day, I was asked to play in a game. I'm having a tremendously fun time. A big part of that is certainly the fact that Jason is an extraordinarily good GM.
Best non-tabletop RPG: Fallout 3
Damn. This game is gorgeous... and enormous. It totally makes me see the appeal of sandbox gaming. The voice acting is impressively good. The plots are intriguing and involve a ton of morally gray areas. I've had some truly awesome moments in this game. It is available for PC, Xbox 360, and PS3, but given the huge numbers of downloadable mods that are becoming available from the huge modding community, I'd definitely recommend the PC version.
Biggest disappointment: Tie
D&D 4th edition. I was really hoping to love it to pieces. I didn't. I haven't really had too much to say about it, because I don't think it is a bad game... it just doesn't do what I want right now. Odyssey summed up my thoughts on the matter better than I could, so go read that if you are curious about my opinion.
The demise of our Wednesday night gaming group. Pat moved away. Doug and I were moving in a different direction from Jeff - we wanted more high-powered/pulpy stuff and he wanted more retro/nostalgia stuff. We couldn't find a workable compromise, though we tried valiantly with a Buck Rodgers-esque Savage Worlds game.
I'm also sad that Jenn hasn't been running her Exalted game, but I have hopes that she'll pick it up in January... so I refuse to acknowledge it as a demise...