Ok, so I replaced the card I returned with an EVGA Superclocked Core 216, and it's pretty sweet. After running Crysis for an hour it idles back down to 43 with the fan on auto, and down to 39 with the fan at 100.
Under load the card peaks at 60, both at the default speed of 576MHz, and at my overclocked speed of 710Mhz, which is playing Crysis Warhead using all enthusiast settings with the exception of shadows at gamer, 8xAF, and 2xAA @ 1600x1200. This was with the fan at 100%, and three case fans; 2 120's and an 80mm. I was getting 20-35+ fps with those settings. When running the fan on auto it peaks at 74.
The shader seems to be holding my core back, as I get artifacts at 1435, so I run at 1425 which limits my core clock to 710. It will run fine at 715/1430, but I don't want to push it too hard. My memory artifacts at 2550, so I run it at 2500. That's a final overclock of 710/1425/2500.