I picked up a 478 mobo with DDR2 and PCI-E support. Worked pretty nice, but very limited OC, took my 3.0Ghz Prescott to 3.2-3.3Ghz. Thats also using the stock Dell heatsink tho, so it may be able to go higher. Ive got an 8600GTS in there, havent really gamed with it (use it as a BOINC and Folding box) but I may fire it up and see what kind of bottlenecking I get.
Hheheh, for giggles, may try out one of my 8800GT and my 4870 too