Overall, the best one for overclocking is the MSI K7D Master. It has multiplier and FSB adjustment and voltage adjustment. It is extremely stable and just a great, great board. I have two of them and a Tyan Tiger MP. I had a Iwill MPX2, but it was junk. The best of the one's I have used is the MSI.
I have two XP1600's from Newegg, AROIA stepping (unlocked and modified L5bridges) running along perfectly at 1800 MHz on this motherboard. This is at default voltage. They are good chips, of course, but the motherboard's performance has been exemplary. If I run the chips at default speed, I can set them to 1.45 volts on this motherboard. They run cool as a cucumber.
I bought Samsung Registered ECC PC2700 memory for my K7D's as it would allow me plenty of headroom even at the fastest timings. It is great stuff. Can't recommend it enough. Got mine from Mark One Computers. Their shipping is very fast, but you'd never know it from their tracking system. It doesn't work at all.
P.S. The MSI K7D also has mounting holes throught the motherboard, unlike the ASUS board, so you can mount big heatsinks or waterblocks.
Just hooked up my watercooling system this past weekend and, boy, am I enjoying it. Less fan noise and 45 degrees is the highest I've hit in three days running and I run three instances of Folding@Home 24/7. 39 degrees average.