Matt,

I guess it depends on what you want to use the box for.

If you want to learn everything from scratch, then there is LinuxFromScratch

If you want something a bit easier, then there is Gentoo and Slackware.

Now, if you actually want to use your box, then I'd recommend Red Hat.

Depending on your hardware, RedHat 7.3 makes a very nice package for home
use.
Samir M. Nassar