Well the best 939 chip would have to be the FX55 secondly water cooling wont do if you want to push the chip to the limits on this board.
NL2, Dry Ice or a Tri-Stage cascade cooling will do.
As for overcloking ram have a look at this
370Mhz FSB.
Thats DDR740.
Well in my mind some records are going to be broken with this board.