Keith,
depending on how many system's you need to buy. Take a look at Dell.
Yeah i know everyone and their brother are getting them.
If you are looking for one or two, Dell has their refurbished system's.
Each one is unique with OS and ram etc. So if you wanted 30 of them it would take a while to sift them out.
I picked up a dual xeon @ 2.4Ghz and 1GB of Ram.
Got a crappy 32MB video card but I will be ordering a replacement
one day. Anyways I picked the system up for about half of what it would
have been if I ordered it new and it still has the full warranty etc.
pieter