So long as you don't get a Graphics card block, you can build your own water cooling setup for pretty cheap.
Of course, the #1 cooling method is the MINERAL OIL METHOD.
step 1: remove all fans and case from PC
step 2: place PC in aquarium
step 3: fill aquarium with mineral oil
step 4: set up a fan/radiator/ice pack/whatever to keep the oil cool
Mineral oil doesn't conduct electricity, but does conduct heat. I've seen youtube videos demonstrating this.