PC for FPSes and MMOs. Consoles for anything else. Overall I would say consoles because you can play local with your friends using one system instead of setting up a LAN.
I guess it depends on what you are used to. But a professional player using a controller is no worse than a professional keyboard/mouse player. I used to use a keyboard a lot. But after playing consoles for a while I started using controllers a lot. Now I even use a controller to play PC games. I still do really good.
Pc or console... tough question... cause seriously, I love both of them. Driving, Flying, RPG i love them on consoles. FPS, Strategy i love them on the pc.
Actually I think Xbox 360 is awesome. We have yet to see if PS3 can stand up to the power of the Xbox 360.
i perfer consoles because i like to chat on msn while playing games and you cant do that if you play games on a pc