NVIDIA's reference GeForce GTX 980 is a monster when it comes to power efficiency and heat output - and not in a bad way. The talk of a watercooled reference GTX 980 using an Asetek unit is interesting, as it'll be thought of in the same light as AMD's Radeon R9 295X2.
The GTX 980 pictured above has the Asetek cooler slapped into it, but if you look closer, there's still the reference fan installed. This will see the GPU itself cooled with the Asetek watercooler, keeping it nice and cool even with some crazy overclocking, while the rest of the components such as the VRM and RAM and cooled by the reference cooler.
It would be interesting to see NVIDIA offer out a new reference GTX 980 with the watercooling used above, as the Maxwell architecture has some massive headroom for crazy overclocks, which watercooling will only amplify.