I am incredibly, amazingly bad at first person games. Something about that camera system just does not jive with my brain. If it's a slower paced puzzly-type thing, I can usually get through it (I did finish Portal), but FPS and such? Not gonna happen. It's funny, becuase if you look at my achievements on 360, it says I beat Halo 3 on Legendary. Truth is, my fiancé and his brother beat Halo 3 on Legendary- my job was to stay just out of combat range and act as a spawn point.
I also don't like tank controls- I can play through those, I just don't so I'm bad from lack of experience. It just feels awkward to me. I can only think of one tank control game I really enjoyed off the top of my head- ironically, it's Jumping Flash. Which is also first person, so you'd think I'd really hate it- but I guess the two together work for me? I dunno.
My best games are 2D platformers (like any good gamer raised in the 80s), Beat 'em ups (I used to be able to beat Streets of Rage with my feet), and rhythm games (very relaxing, just tap along to the beat. Usually, anyway.) I also enjoy shmups, but I can't rightly say I'm good at them.