Single Thermi (480gtx) idled around 50C and load was max 87C. One thermi, apart from what people may think, is quite a nice videocard to live with. Not that loud although hot, but I don't have to touch it, hehe
My Thermi (480gtx) sli was idle 56C and load 93-95C top card; and idle 50C, load 85C bottom card. 480 gtx in SLI noise levels were not tolerable for me with the stock cooler. I understand that some folks can live with it and be happy but I couldn't. So, I did the unthinkable: downgraded to a single 580gtx!
My Fermi (580gtx or 512gtx as I call her in private), in the other hand does 35C idle and 58C on metro2033 (around 53C max on Assassins Creed Brotherhood maxed-out) and I cannot even hear the d*** thing!
All temps are stock clocks, fans on auto-profile and ambient temps of 25C nearly constant.