I've been asking the same question till I was blue in the face last few months, with no coherent answer...
one thing is, the fan & heatsink you got with plain retail CPU is louse, you should upgrade it for sure...
other than that, temperatures are hard to gauge because they vary by CPU load, particular motherboard you have, particular revision of that motherboard, particular bios you're running on that particular revision of that motherboard; how close the thermal diode is to the CPU; how well the diode is working; which software you use; what's the external temperature; whether the gods are on your side today...
I actually get a lot higher temperature from my 1.1Gig, almost 140F reported... but it works fine, it has a ChromeOrb professionally installed with arctic silver on it and 7 fans total in the case -- this baby is actually quite cool inside... besides, the BIOS shows temperature almost 20 degrees lower than my software (newest ASUS probe) does, and the temperature doesn't vary with my CPU load more than a few degrees (most people get much bigger differences)...
so its pretty hard to tell... one guy's experience has little to do with another's...