Well, I got the Dothan running on my P4P800-DX, but it's pain. None of the Asus bioses are really ready for prime time yet.
I do think it's funny all you guys are sweating over heatsinks and cooling. High-end HSF's really aren't necessary - the Dothans are 27 watts, maybe 33 overclocked. At some point, you really aren't getting much of a return, since you get so close to case temps, at some point you won't get much cooler unless you go to a chilled/vapor solution. The stock heatsink barely gets warm. For this reason, I think water would be nearly useless over a decent copper HSF (notice Macci is using
chilled water, a huge difference since hs is going sub-ambient).
Your
real concern is getting the right board-bios combo.
This thread details the issues with each board. Remember, a lot of these uber-clockers are using extraordinary measures to set voltage and multipliers (most people are setting these high clocks in Windows using Clockgen), not to mention cooling. And flashing one of these boards is no cakewalk (unless you have a 478 processor to boot it from to flash, good luck!).
Right now I think the board to get is the P4P800-SE, but even that has some issues.
This is done on a stock 6800GT and a very low FSB - can't really adjust the multi on this board.
I am sure under the cascade I can get this thing running at least 3.3, but without the ability to change the multi, it's wasted clock.
Sorry to rain on parades - at some point if Asus releases some good bioses, this will be a cool gaming platform. It's just a little early.