First a heads up on my plans:
-SLI 8800 GT's
-lightly OC Q6600
(w/ appropriate CPU liquid cooler)
I'm planning to grab a CPU liquid cooler only if it will enable the following:
-i can disregard ventilation and just go for the flashy looking and soundproof cases
-i dont have to worry about the SLI 8800 GT's overheating
-i wont have to go solid state, and stick with the noisey raptor in silence
My ultimate goal is to have an absolutely silent machine that has some power.
Of course, I would also like to do all this without having to worry about my frikin temps.
You will need case fans, two 120mm on low. The water cooling will need two 120mm fans on med low depending on what you buy. Adding a GPU watercooling means a bigger rad and more fans. Any hard drive makes noise. The SS drives aren't big enough yet.
A quality WC rig for the CPU/GPU will be in the range of $350. Oh wait, two GPUs? Add another $80 to that.
Watercooling isn't silent, but it's quieter than 2 delta 38mm fans at 110 CFM screaming at you.
For your benefit please spend a few days reading a LOT. Here and at the busiest places for WC masters. Guys who have done it for YEARS at OC forums and xtreme forums. It took me a while (I was OCing on air, aftermarket stuff, bios settings, best chipsets etc etc) to learn the language and the tricks to a easy install.
Don't expect miracles, or SUPER DOOPER over clocks. What you will get is a quiet system that can handle OC to the max of your hardware IF you buy quality and buy smart. And minor maintenance too, a bonus for the water cooler.
Also while there please read on case mods etc. The radiators are not for small cases, the pumps and hose routing, wire management and other things are important to understand. Google your planned case and the word water-cooled in one line. You might get lucky.
IF you just cool your CPU and your NB if you want, you can get by with a 120.2 sized radiator (RAD). And MAYBE fit in inside depending on your mod skillz. You want to cool your GPU too, you'll need a 120.3 sized rad, and it won't fit inside. The rear external rad really works great. No matter what your adding 15lbs to your PC, maybe 20lbs.
Once you got an idea of what is good/bad then start getting your system for WC put together and we'll be glad to help.