FPS, TPS, Puzzle, Adventure, RPGs and most strategy games, I am fairly good at. Actually, with FPS I'm usually above average (although I never become an expert).
However, Racing, Fighting and Real-Time Strategy games are the bane of my existence - with Racing Games, either I can't get over the fact that the computer "rubber-bands" its way to victory or I can't be stuffed "modding" the car to win. With Fighting games, I just can't get the timing right, or bother memorizing all those moves, and with RTS - I just can't click that fast.