I've been keeping an eye on eBay for a long time (1 year +) looking for a great deal on a local G5, and I finally found what I was looking for.

Power Macintosh G5 2.0 DP (PCI/970fx)
ATI 9800XT 256MB
2GB/320GB

$280 including tax

I'm going to fill the rest of the RAM slots as cheaply as possible, transplant a USB card, and maybe try to find a cheaper low capacity SSD for the OS. Looks like I'm set for another 3 or 4 years.

Still clinging to the G4 with my 12" though...