With the difference between the athys and the durons being about $20, get the Athy, the pure clock speed doesn't matter as much as the on die cache. Any DDR mobo, Asus, Abit, Epox, are the companies I've had luck with. Something with a 333Mhz bus for RAM and an ATA 100 or 133 controller so you can get the most out of your harddrives. That and make certain to get some name brand DDR ram and you'll be set. www.pricewatch.com
is about the best place to find anything, if you didn't already know that.