As I mentioned earlier today, Layla and I went to Fry's last night and bought us some hot hot hardware. Since the hardware doesn't need babysitting at the moment (it's copying files from the old server), I'll tell you a bit about what we picked up.
It's somewhat difficult to get serious 32-bit hardware these days, so we went 64. In specific, the new fileserver ("shake"—I'll tell you about that later) is running an AMD Athlon 64 3000+. I tried to get the 2800+ (because although I can't tell a performance difference between a 2800+ and a 3000+, I can tell a difference in how heavy my wallet is) but Fry's didn't have any in stock. The part we ended up with is a socket-754 part, and the only reasons we went that way was (1) the -754 motherboards are way cheaper for the same toys, and (2) although I know the -939 boards are more upgradable, I can't ever remember actually upgrading the CPU in a motherboard. By the time I get around to looking for a new CPU, the motherboard is completely obsolete, too. I'm just not on that quick of an upgrade cycle.
The board itself is a Gigabyte GA-K8U cheapo board thingle. It seems like all the chunky boards these days are fitted for overclocking, which means that I'm likely paying for a bunch of features that I'm never going to employ. Now, I thought we bought the GA-K8U because it was a cheap ($65) board that had an nForce 3 chipset, but looking at the specs (linked previously) I think I've been had. This board has what looks to be a total POS ULi M1689 chipset instead of the nForce. I think Fry's must have gotten their cheat-sheets wrong. Bitches.
Anyway, we've got this rig rounded out with the Biggest Heatsink In the Western Hemisphere (photographs pending) and a solid gig of DDR400 RAM.
I would talk more, but I'm a bit sore about the chipset. Aaagh bitches!
I'm having the opposite problem of what you mentioned. I have CPUs I like and want to upgrade the motherboard. It appears that I already have nearly the best board the CPUs can go in, so I'm SOL.
I've seen the ULi benchmark better than than nF3 chipsets (you didn't mention which version you thought your board had). nVidia bought ULi last December for 52$M, as I'm sure you've heard by now. They used to make some great chips.
I have to admit that I'm not much of a hardware nut—I'm not at all familiar with either the ULi chipset or, really, the nF3. I've heard purely anecdotal evidence that the nF3 performs better under heavy load conditions than the lower-priced alternatives.