Here are the temps for my Leadtek o/c at 800/1600 MHz, in BFBC2, with a "mild" custom fan profile in MSI Afterburner: 72 to 74 degrees C, fan @ 60-63% (can't hear it in my case), stock voltage 1.037v. Ambient temperature ranging from 25 to 26.5 C.
Custom fan profile is the one suggested by MikeC, with minor modifications. Before I was using a far more aggresive fan profile - 70% fan @ 70 C...
Tested in other games, too. Perfectly stable... but what puzzles me is that the temp differences between stock clocks and o/c only are only 2 to 4 degrees C. At stock clocks, BFBC2 brings the core to 70 to 72 degrees C.
It will go up to 850 MHz on stock cooler, stock voltage... but I really don't see the need for that. It also idles at 40 to max. 45 degrees, at least 5 degrees cooler than my older GTX 280.
To conclude: couln't be much happier with my GTX 480