Originally Posted by GhostGT
Definitely build your own.
I've done both; bought pre-built systems when I was younger, but I build them now.
Chris' advice is pretty sound. I started building systems with an XT (what a nightmare that was... learned the hard way about "parking" MFM and RLL hard drives). Building you own can be more expensive if you're buying premium components, but then you get a better system for the price. His advice about making sure components work with one another is important to pay attention to (not just making sure you're using a PCI express card if you have PCI express, but using RAM recommended by the manufacturer).