Agreed! Under stress my cards (2x GeForce GTX 550 Tie's in SLI) jump up to 64⁰C max ( 147 F) and just keep purring.
I can't comment on the ATI/AMD cards because I don't know them that well. My two 550's w/ 1Gb memory perform much better than a 560 and just about as good as a 570 (as per several reviews and benchmarks on-line). I play COD WAW (and get 200-300FPS - I unlocked the maxframes) and BF3. Both games just fly at max screen resolution of 1920x1080 and graphics options on high. A single 550 TI is...meh, Performance is just "good enough", but FPS is mediocre. Two cards perform greater than the sum of their parts, which is crazy. If I were you (just quoting nVidia - there are equivalent AMD cards) Get a 560 or 570 and budget for a 2nd card eventually when prices drop. The 550 series w/ 2 cards is great for now and awesome value, but could be dead-ends projected 3-4 years out. Within that timeframe, these cards in tandem just rock. I'm more than pleased with their performance with the games that I play, and the price is very nice.