What are you on? Can a XBOX be used to write a paper, solve equations, take to school, do homework, and browse the internet/NS?
You're comparing apples to oranges here. PC's are made to do a lot more shit than just play games. XBOX's are made to just play games and the whole system is designed around that. PC's are made to get work done and also provide entertainment.
That being said, I'll take my desktop and laptop to play games anyday rather than on an XBOX. No controller will ever give you the feel that a mouse does when gaming. I used to hook up a keyboard and mouse to my original XBOX and pwn the shit out of people in Halo LAN parties.