I used to use lots of different programs to monitor everything with a sensor, but I guess it's my old age that has me using CoreTemp or RealTemp to monitor my core temps now and that's about it. Once my OC is set I may stick my hand in the box to make sure there is enough air flow over the passive heat sinks (since I'm on water) so they are not getting too hot when running Prime but that's about it. I just finished a review on a set of Ballistix Ram with the built in thermal sensor and really had to hold myself back from stating what a waste of time I think a thermal sensor on DDR3 memory is.
But, either way, if you use Everest,HWMonitor, CoreTemp etc. just realize that they aren't perfect and sometimes can give crazy reading (like you know already).