Yeah, but my point is that there are dozens of different types of 'server's. You can have a web server, a database server, an authentication server, DNS server, DHCP server, RADIUS server, telephony server, game server... It depends on what you want to use it for. There's also the question of what OS you want to run. Windows (expensive), Linux, BSD etc.
However, little of that has an affect on hardware. If you're running a low usage something, pretty much anything is fine.
If you want to do a Linux based webserver, installing Ubuntu Server Edition is probably a good first step. However, I wouldn't recommend that for production systems; you'd want a hardened Red Hat or similar.
You can write web pages on your own system without any kind of server though, or use a free webhost online.