#1, if you're not O/C'ing, you may want to wait for San Deigo and pick up a 3500/3800 or better.
#2, I'd pick up a nForce 4 Ultra board. May not need the DFI if you're not going to O/C for sure, but the Asus is really good and stable as is the MSI, Gigabyte and Epox I hear.
#3, no need to spend a lot on ram, just get decent PC3200 and perhaps some lower latency modules since you won't be O/C'ing.
#4, get a decent Power Supply like the Seasonic 430W Definitely the
Sparkle 550W w/36A on the 12V line for about $110 DEFINATELY THE SEASONIC 430/500/600 OVER ANY SPARKLE.....QUIETER, BETTER COOLING, MOST EFFICIENT PSU ON THE MARKET SEASONIC 500W
#5, Video.....like nVidia or ATI? 6800 Ultra or X850XT......SLI??
Definitely SLI for that budget, dual 6800Us Persoanlly, I'd take the X850XT over the SLI......but that's just me......I don't look for SLI to have longevity and with new cards due in May.....