I wouldn't mind watercooling my cards. My CPU is, and comfortably sits at 4.6ghz. My EVGA's can be quite loud as they have shroud coolers, and the lack of noise and 5-10c lower temps would be nice. I understand the theory, it's the dismantling and putting back together, and all the plumbing, is a little beyond me. Pity there isn't a place to have it done for you, for a reasonable price of course!
My dream is a totally silent rig. For months I was working up towards buying one of these, but the cost of getting it custom built + shipping to Australia + GST - without even getting to the component stage - forced me to shelve it.