server setup

[oOo sam lee oOo]

just curious....what would it take to build a server thats used to like...host other ppl's sites and stuff...you know those places where you buy hosting and make ur site and stuff...

what would i need to get? ive heard stuff about how the opteron and xeons are good for servers, but why? and would that even be too much for this? I'd just like to know as much as i can about this

thanks