What OS? And what are your idle temps in the BIOS? I've downloaded 3+ programs (Intel TAT, Everest and SpeedFan) and they all vary wildly in Vista. I'm getting low-mid 30's C in the BIOS with a Zalman 7700-alCu and doing load tests in Everest gets low 50's max.
Bottom line is are you having any throttling issues or shutdowns? Try a few different monitoring programs and see if there's a major difference in reported temps.
Despite what Everest or TAT says, I used to get about the same temps from my A64 4000 with the same heatsink in Asus Probe and I can tell the Core2 setup is cooler - one real easy way to tell is the room isn't as hot and I don't feel the same amount of heat coming out of the back of my case.
That being said...check the way the cooler is seated on the mobo. Intel coolers and their plastic pins have a way of feeling seated when they're only halfway locked.