I had my '88-'94 platform hayday predominantly consisting of the side scrolling Mario & Sonic games amongst a few others.
The only fighting game I ever got really good (& I'm talking ridiculous) at was the original Bloody Roar for Playstation
As far as Shooters go, I got pretty good at the first couple Twisted Metals
FPS, I'mma go with Quake 3, Unreal Tournament (excluding 3 as for some reason I'm not as good at that one), Battlefield 1942 (Desert Combat Mod)
Racing, I'm not too bad @ Need for Speed: Most Wanted & most others that involve police chases :p
RTS, Starcraft I can hold my own (there're plenty who're better at it than I, but I'm pretty damn good), Command & Conquer: Generals & Zero Hour are pretty much my bread & butter until I get more of a feel for Red Alert 3.
I'd count RPGs since I've spent more time playing those than any other genre, but I can't say that I'm good at them (how does one compare RPG ability outside of MMOs?), I just enjoy them, I don't power play through them. But yeah Final Fantasy, Lunar, Chrono Trigger/Cross... good times
I kinda wish they'd do a Final Fanasy Tactics online..
When I want your opinion, I will diffuse it from you through osmosis!