Fantastic Plugin! Rated 5 out of 5 stars
Distrust allows you to temporarily disable all the history Firefox keeps of your browsing.
Distrust is the first plugin you should install (okay, the second after AdBlock Plus)! Other reviews say Distrust is not necessary because of Firefox's built in "Clear Private Data" feature, but I totally disagree! I leave distrust off most of the time so I still have browsing history, but turn it on when I'm visiting sites that I don't want my kids (and wife!) to see in the history!
If you want no history of anything, then use what's built in to Firefox. If you just want to erase parts of your history, use Distrust!