Hey Lego- my 5750 runs between 70 and 75 when used below one of those 5850s that throws heat everywhere instead of exhausting, or 45 when mining just by itself at the settings below.
Some other little stats that might help you..
on mine at least, 910/270 is the magic running spot and produces 189.2 Mh/s, using guiminer with -k phatk FASTLOOP=false VECTORS2 WORKSIZE=256 aggression=13, as a non-monitor card, affinity spread across 4 cores. I usually run it limited to one core though and with worksize at 10, which when mining with other cards shaves quite a few watts usage and drops only 2 mh/s.
Well I feel safer knowing the ~75 is bearable. My 5750 is the kind that spews heat everywhere. Thanks for the other stats, I'll give the tags a try in a bit.