I have been digging into the reasons for the Firefox crashes and its heavy memory usage. Following links did throw lights on various Firefox extensions and also gave me lots of workarounds to improve my experience with Firefox.

Tips and tricks to Reduce Firefox Memory usage

Firefox – Flash Memory usage

Problematic extensions and WorkArounds

I'm sure you too face this problem often with your Firefox. Have a look at these links and remove those buggy extensions and rock on floor.