For a while, Firefox was crashing Linux as well, probably from some accelerated graphics bug. (It used to happen sometimes when ArsTechnica would play an ad, for example.)
Whichever version of Ubuntu introduced pulseaudio crashed any time Flash was used on a website, often in ads. May have been that. I mean, Pulseaudio crashed xwindow (or just stopped working) all the time in that version, but Flash was the easiest way to kill it.