The build looks good. My suggestions would be to step up to the GA-EP45-UD3P so you have the option of crossfire later on. The PSU you selected will run two 4870's, so you might as well leave that option open.
Multiplier not very high and less cache than Q6600 so you should be able to push the Q6600 higher than the q9300. The pentium 4 HT Mobile 552 in a desktop with a nice HSF probably was an overlockers dream with a multiplier of 26 and it being a laptop chip.
agreed...can push Q6600 higher but that doesnt always mean better performance. Have been reading tons of forums with the debates on E8500 vs Q6600 vs Q9300. I do agree though, the 9300 is much harder to OC due to FSB (if I am correctly understanding what I am reading). The extra cache in Q6600 would be beneficial for gaming as well.
Just wanted give a shout out to all at Toms Hardware !!! All the forums and the feedback have been enormously helpful. Here is the Rig I'm going with (Already placed the order) woohoo!!! I think it has a nice balance for some OC'ing, some gaming, some video encoding, and the ability to upgrade/add some components in the future. Still need to get Vista 64-bit. I have a buddy who owns a PC repair shop so I'll see what kind of a deal he can do for me on the OS ;-)