Best PC temperature and fan-speed monitor software???

I have a Dell 530S desktop that despite being 100% dust-free inside, is locking up with the fan on high, which sounds like an overheat issue. I can hear a little bit of odd fan noise, so I bet a fan is on it’s last legs and spinning too slowly.

Any favorite utilities for this?

I run XP Pro on this PC.

I was planning to give SpeedFan a try and grab a copy of the Dell Diagnostics for this machine, but if there is something better, I’m all ears. Speedfan can show fan RPMs, which I am guessing is the problem in my case.

SpeedFan
http://www.almico.com/speedfan.php

HW Monitor
http://www.cpuid.com/softwares/hwmonitor.html