Many, many options... ATI chipset boards are coming out in droves (well, it appears that way...), many of them have great reviews. Since they're still new enough to not have much history on them I haven't made a decision on who's is best there...
Generally for overclocking (which the ATI's are supposed to do well also) you would get an nForce 4 chipset. DFI makes the best OCer, but it takes skill to configure it right. Epox is 2nd best and is easier to configure. ABit, Chaintech, Gigabyte, etc. are fine too - ABit has the uguru OC software for beginners. Asus usually does well, but for ocing only the top end A8N series seemed to OC well (the Premium IIRC), and you pay a premium for the premium... :roll:
Get some OCZ RAM - the Rev.2 stuff is supposed to OC like mad... but don't worry too much about ram because running on a divider on an A64 doesn't hurt performance hardly at all.
Mike.