I had a Chill 1000 watt PSU, I do not remember more, because I sold the remains as soon as I could.
A lot of wires had melted in the case around the GPU, so it was in pretty bad shape. I had the Phantom craftes series tower with 1 x 200mm, 1 x 140mm and 2 x 120mm fans, so the airflow in it wasn't either a problem, if you might think that.
I would guess it was a PSU issue, I am assuming that is one of the "no-name" brand PSU's, and the power supply is the most likely component to fail and fry other parts (which is why most if not all of the experts here recommend going with one of the main brands). I don't think your GPU went bad, especially if that was your average temp on it. Don't worry about the heat of the new GPU unless a) a monitoring program is showing high/outrageous temps (or you feel the heat from the card is collecting around your CPU, raising temps there), or b) you start having video related performance problems.
Sounds like he doesn't have the 660 yet Thent, he is just looking at the performance benchmark temp reports out there.
yes, like i have said those temps are very good, and the ambient temps will change value too. i have a 680 here, and i'm from brazil, so when i the day is hot my gpu goes over 80 celsius, on days tha the ambient temps are low i barely get to 70
these values are under stress too.
My old 9800gtx+ on some days went over 90 celsius and i kept playing, it still working today...