I keep my thermostat at 68F. My inlaws have it set to 74F and I fry everytime I go over for the holidays. Of course maybe when I turn 80 I would want it that warm. I feel like wearing shorts. 
The only bad thing is the heaters in the tank seem to always be on.
A sweater is all you need to stay warm and green.
135g Main Tank/ 125g Frag tank with 55g sump.