Todays gpus, even high end, if you chose carefully, you will end up with quiet setup. Brands that have been quiet over last 3 gens have been MSI, to some point Asus, now a days EVGA, Palit and Zotac are doing good jobs on quiet operation on their latest gpus, but not on all models you do need to chose carefully.
Now is there are a place for water on quiet computing? definitely, but to me is on SLI of high end cards, where air starts to suffer due to the space restrictions and the heat building makes air not as efficient, i experience a lot of noise with SLI of Asus GTX970s, and then a lot lower with MSI GTX980Ti, but still on demanding games and hot days.... it was noticeble to say the least, i do think i would have ended with a much quieter setup if i were to have gone water with either setups, now im back to single gpu and its fine on air.
To recap, i do think watercooling GPUs is a good idea when you either going multiple gpus or if you plan to OC.
GameMiv3 >> AsRock H170 Pro4 | Intel Core i7-6700K | Prolimatech Genesis + 2x Thermalright TY-147A | Kingston HyperX FURY 64GB DDR4 2133 | MSI GTX1080 Gaming X | Acer Predator XB321HK 4K IPS Gsync | Samsung 850pro 1TB | WD RED 3TB | Silverstone FT05 + 2x Silverstone AP182 | SeaSonic SS-860XP2
Other builds ---> ServeMi | CamMi | MiniMi | HTPCMi