I have read a ton of reviews on the KT600, and after seeing all the problems that people seem to have with the nForce2, I think the KT600 chipset will be on the next motherboard I buy. Really, though...I don't see why people think the nForce2 chipset is so wonderful(it's good but not great). Albeit the KT333/400 aren't as advanced as the nForce2, they really are just as reliable if not moreso. I still use a KT266a board and love it. I was gonna get an nForce2 board because I hate waiting, but I think it's gonna be worth the wait for the KT600. Should be out in a few weeks to a couple months, and if I remember correctly ASUS is going to be the first brand to use the KT600.
-drew