The GTX 470 and GTX 480 Hydro Copper FTW drop the large heatsink with the loud fan and will instead hook up to your liquid cooling system, while still featuring a rather high factory overclock -- and a premium price tag to go with it. Both cards get a 50MHz speed boost to achieve 650MHz and 750MHz core clock speeds, respectively. Shaders and memory have also been bumped to 1300/3402MHz on the GTX 470, and 1500/3800MHz on the higher end GTX 480.
It's interesting to see these cards announced already given that Nvidia said only models based on the reference design would be available at launch. In any case, the GTX 480 Hydro Copper FTW is set to sell for $650, while the GTX 470 HC FTW is $499 -- which is actually not too bad considering water blocks can easily reach prices around $70-100.