if you going for that get a Gigabyte GA-G1975X.
but im gonna sugest something, the pentium D 950 is arounf $340, but you can get an opteron 165, which is much better than the Pentium D and overclocks more, for $325.
or if your gonna go intel, i think there gonna release a new chipset soon that will support conre, so if it comes out soon just get a pentium 4 631 and tough it out until conroe.
Why the opty is better than the PD: im pretty sure it has to so something with the memory divider on the Pentium D, plus intel dual core arcitecture is all messed up but they fixed it with the dual core conroe chips.
ask around for info on why the opty is better exept for overclockability.
Go for the pentium D 950 and overclock it to arounf 5.0ghz if you getting water coling or anything better, otherwise get the opty 165/170 and oc it to around 2.6ghz, which is a good overclock if your a beginner.