x64 !!!
After playing around with the Quad core, I tried once again to install my 4x 1gb Mushkin redline modules. Eventually figured out that one of them was bad, so submitted an RMA request to have that replaced. 3x 1gb would work, however I was still rather peeved that I was only getting ~2805 MB of RAM due to 32-bit Vista limitations.
So today decided to preemptively install vista 64-bit. 1) just to see whether or not performance would be snappier, 2) just because I had some time to kill.
The first time, I attempted to load a check/debug version, which never even made it to the main install screen. Everytime it would BSOD, due to my SATA DVD/RW being plugged in. Eventually I got it to install, then decided to reinstall using the non-debug version.
Overall, performance and compatibility has been fairly good.