Greg,

I currently have over 10 GB of MP3s that I can play through my home theatre. It's not all that complicated to set up:

I networked my 'main' PC (500 MHz, huge hard drive) to my basement PC (Pentium 150, cost me $50). From there I bought a new 32 bit sound card ($15) and ran cables to the CD Input on my receiver!

The hitch- choosing songs. Currently, I use a scan converter ($150) and use my 32" TV as my monitor, but it's damn near impossible to read. I'll end up with a 14" monitor sometime, when the wife picks a place where it doesn't look too bad :)

Also, I use a wireless keyboard/mouse ($50) so I can do it all from my lazyboy.

In all, it wasn't that expensive, allows me instant access to my whole MP3 library, and sounds great!