Uh I own an XP 2700+ with a Thermaltake Volcano 7 heatsink/fan. Now the case temperature is 26C, while the cpu temperature is 49C. It's always consistently a 22C difference, and with NO overclocking. Is this accurate for the processor and heatsink that supposedly has arctic silver 3 applied? Sounds very high for a computer that isn't overclocked.

49c isn't bad for a Volcano 7 on a 2700+, if that is load. I'd say that is very good. I have a Volcano9 on my 2400+ and run about 42-45c load.

Heh yeah but this is idle, and the case temp is a mere 25C.

Well, that Volcano 7 isn't exactly rated for such a fast CPU. I thought it odd that you had such good temps with that cooler. The case temp is always going to be a good bit cooler than the CPU core, unless you use a freezer to cool it. I'd get a better cooler for it if I were you.

What setting do you have the fan at?
It has a low, medium and high setting. You might get better temps with the high 6000rpm setting, although you will have to put up with the increased noise. Maybe a better heasink is a better option

Canada + No heater + Long winters do that

But now that summer is coming up with no air conditioning, you're seeing the true temperatures.

It's at 5100 rpm right now.

What heatsinks are recommended for processors between 2700+ and 3000+ (just want some leeway, and I'll probably compare prices)?

I wouldn't worry, as 22 deg C above case temp is reasonable for your CPU. What is surprising is that your case temp is at 26 deg C (it must be pretty hot in your room). You should also be aware that temp sensors fitted to mainboards are not very accurate and can easily be out by a few degrees.

Also, I changed to Arctic Silver 3, from standard goop and didn't notice any difference whatsoever. If you aren't experiencing any instability then I wouldn't worry, as your CPU can operate at much higher temps than you're getting. If you are really concerned, then do as others suggest and get a better cooler.

Just curious, but is there any chance that the temperatures can be recalibrated?

Not really (not impossible, just not practical), but it doesn't matter much as these sensors are mainly provided so that you can detect when things are abnormal. They also allow your bios to shutdown your PC, or throttle back your CPU if the temps get too high. As long are everythings stable, then you don't need to be concerned with accuracy, a few degrees is nothing.