The -X model uses the nForce2 400 (non-Ultra) northbridge, which means it doesn't have the dual-channel ability of the standard A7N8X or any of the other A7N8X family. Last I knew, it also didn't come with a Gameport & dual-USB outlet plate for the PCI slots either, so if you need those, might be worth getting the A7N8X standard.
Shuttle AN35N Ultra is a competing board that's worth a look too
It has the dual-channel Utra400 northbridge and also uses the ATX12V secondary power cable from the PSU, which is not a bad idea since it spreads out the power load across more connectors. It OC's pretty well and doesn't cost much.