Maximum cpu temp, how many fans?

My 13 inch unibody Macbook is currently running at 81C. Isn't that high? What's the maximum temperature? The fan(s) run constantly.

I have a fan utility that lists 2 fans. The "Left" fan is at 6204 rpm's, temp 81.4C The "Right" fan shows 0rpm's, temp -1C. Is this merely because the sensor is capable of recording two fan speeds or do I really have one malfunctioning fan? (which would explain the high cpu temp, if it applies).

A third sensor, a widget, records the same temp, with Heatsink A 70C and Heatsink B 64C. I realize all three sensors are getting their readings from the same spot; which one do I rely on?

EDIT: the only program I'm running (visably) is FireFox.

No Flash, no Java. I use a Bluetooth mouse, I just turned it off to see if there's any difference. I also rebooted so the temp went down during the 2 minutes it was off; the temp right now is 72C and slowly climbing.

Thank you! GeekTool was using ~40. I Forced Quit and my temp dropped 20+C, now at 49C. Thanks-a-bunch, I wouldn't have thought of looking there.

Coming from Linux I'm familiar with those commands but had forgotten they work on Mac OS as well. Thanks for reminding me!