@Jeff
Pick up a PC Geforce FX 5200 and flash it. You will probably need a friend with a PCI video card and a spare PC to flash it with. Made a night and day difference with my AGP 400 Sawtooth. In fact it can run WoW (albeit not playable in very populated areas) even though its 500MHz under min specs.
The GeForce will really make the machine sing at 533 and it will be gorgeous if you upgrade the CPU.