The ceiling temps, afaic, are also entwind with Intels idea of how long the cpu should last u, temps over the life of the cpu. Their boundries for a healthy install - I guess.
The clocking community, maybe mobo manufs too, would probably advise that 85deg as an absolute maximum to run a 1-off benchmarking run. Not something to stress the cpu over time at tho, and many mobos are default to shutdown at 85deg.
Electronically, I believe the Q6600, atleast the G0 version, has a maximum sensor temp of like 100/105 deg or something. And it`ll use this as a reference to report temps to the pc - i.e. how far from 100/105 u are. The clever software does the math for u and gives u the temp u report.
If ur stress testing (running all ur cores at max over a period of time) a mobo/cpu install, C2D in general I think, 70/75 deg is a sort of self warning that ur just around the temps where u don`t want to go any higher. Considering that hardly anything with run all ur cores at max during normal everday use, even when u run ur games etc, this is a good point to stop and settle at that oc.
Outside of normal use, u get people who run the likes of Folding platforms 24/7 - this is exactly the same as running a stress tester, similarly if u like to run benchmarking programs all the time. In these situations, I`d not like my cpu going much over 65. This allows for any change in room temps, and also gives u that much more lifespan to the cpu.
The 60-something u got is not a temp to be alarmed at - if this is at a point where u got all cores fully loaded. If this is idle, u have a problem, particulary if ur using water cooling.
I`d have to ask what temp reader is giving u the info also, some are grossly incorrect, some are closer.