EVGA representatives have confirmed that in Europe, they are happy with the sales of the Geforce 8800 GTX Black pearl water cooled card and that people are quite interesting in buying those.
Water cooled cards probably can overclock even more and such a card will definitely offer a very quiet environment.
Some of these cards can even hit 680 MHz clock speeds and you definitely need water to hit such a speed. Nevertheless such a high frequency is already dangerous and can fry your card. EVGA 8800 GTX Black Pearl ends up around €100+ more expensive than the reference card but it has to offer a faster frequency and a quiet environment.