Have you considered the MSI K8N Neo board? Top rated, with the new NForce3 250Gb chipset. If I was going to get an Athlon 64 (and I personally would, over a P4), this is the board I would choose hands down.
As for Athlon 64 's 64-bitness being useless, I think there's a lot more to it than just 64 bit instructions. The Athlon 64's onboard memory controller and enhanced FPU already provide for some significant performance increases even in 32-bit environments, and the chip is likely to scale better. With the knowledge that Socket 939 Athlon 64's will be nowhere as inexpensive as we had hoped (at least so far) it appears that Socket 754 will be around for awhile as the enthusiast's choice in the Athlon 64 market, so I don't see anyone running out of headroom to upgrade for the next 1-1.5 years, which is pretty standard in the enthusiast PC market.
Toss in the features of an Nforce3 250Gb mainboard (onboard gig ethernet, SATA, hardware firewall, fast Hypertransport bus) and you have a potent combo. I have nothing against the Pentium 4, but a P4 performing similar to the Athlon 64 comes at a higher cost, and will probably not have the longevity that the A64 does, as new 64 bit apps will extend the life of the A64 you buy today.
Intel Q9450 @3.2GHz, Gigabyte GA EP45-UD3P, 4 x 2GB G.Skill @4-4-4-12
Antec P160SW case (modded), Xigmatek 750w PSU
3x 500GB (RAID-5), , OptiArc 7200S, ASUS E818A3T
Creative X-Fi XtremeGamer, Hauppauge HVR-1800, Radeon 4890