you might not like AMD, but wait for the reviews of the 4870 to come out, and see if you might wanna pick a pair up... Unless, of course, your budget allows 2xGTX280. your system will kill with these two.
For extreme cooling... I guess you can start looking into phase. Water is as far as I have gone, and it's great, but not extreme.
for cpu, i would go with a Q, not an E. Crysis does scale better with a quad-core. the E processors are dual cores, X=dual-extreme, Q=quad, QX=quad-extreme. again, i'd suggest a quad core, and the mobo will somewhat affect your overclock potential.
I haven't been looking into PSU's but with a pair of graphics cards, you'll want a higher-wattage one for sure... 800w-1kw to be safe
as for mobos... welllllllllllllllllllllllll kinda depends if you're gonna decide between nvidia or amd!