Agreed. I'm running an AMD64 3200+. When I upgraded, I did so from a VIA
KT133 chipset and a 1.8 GHz processor, so the improvement was significant.
Your system is still relatively modern, and will do everything you need it
to. Wait for the NForce 4 SLI chipset w/PCI-e. Give it till after Christmas
and a few months to discover significant "bugs" to be worked out and then
upgrade. By then, prices may have stabilized a bit, and you will be much
closer to the "cutting edge", and see more of a performance improvement.

Fitz