Without a doubt I'd go for the ASUS A7v ! It's supports upto 1Ghz Athlons/Durons, can support 4 IDE drives (2x UDMA100) and can support 7 USB ports! It's also the fastest board available and the most stable and I should know I run a network of 30 computers and they've all got A7v mobos with 600Mhz durons 😉
The only downside is that AMD has just released a new chipset which supports DDR-SDRAM and 266FSB.