I don't know what the availability is like (porbably limited), but Abit have just released the KT7a and the KT7a-RAID - with the KT133a chipset. The KT133 was crippled to not give fsb speeds much higher than 110MHz if that, but the new 133a will give a true 133MHz fsb, without stressing the rest of the system (pci slots etc). It's supposed to be much better for ocing than the KT133 boards, i think there's a link on the homepage about it. If you can't get one of those, go with the A7V or the KT7 (with or without raid). I have both and there's nothing really to choose between them - A7V seems to give more volts than the KT7, and has more space around the socket, but the KT7 has in bios multiplier adjustments - the list goes on.
UPDATE: Just spotted something over at hardocp, came from tom's hardware initially - says there may be a design flaw in current KT133a boards, and they'll have trouble going past 1.5GHz - a problem if you want to upgrade processor in 6 months time. Dunno how long it'll be until the 'proper' KT133a boards come out, but it might be worth just getting a normal KT133 board like the A7V or KT7 now anyway, if you're going to have to upgrade for the next line of processors regardless.