Turn Based Tactical games, it's like a more complex chess in some ways and I do rather well in them.
Real Time Tactics like Full Spectrum Warrior, SOCOM: Tactical Strike, and DoW2. I vastly prefer real time tactics over RTS because I just feel there is a heavier sense of strategy involved as you have very limited resources and can't just "build" more troops at the drop of a hat.
Fighting games, mostly 2D. I'm no pro, but I am a very quick learner and can hold my own after a few hours of playing a character. I can learn multiple characters and get down their various nuances fairly quickly and dish out at least intermediate combos and what not. Although if I am challenged to a game of Dissidia, I will CRUSH you with almost any character....600 hours of play will make you good with anyone.
RPGs...I guess. I dunno if you can "excel" at an RPG, yea sure there are some tough ones out there, but unless it's an action RPG it's more down to exploiting enemy weaknesses and just general stats. It's not like say a Strategy RPG like FF Tactics or Fire Emblem where bother stats, skills, distance, position, and other aspects come into play and greatly affect how you play.
Shooters are ok I guess, but it really depends on the shooter in question.