UPDATE: In my case the problem was firebug. When a update for firebug came out my problem was fixed. I still recommend taking a look at your profile if your Firefox install keeps crashing even after reinstalling as everything pertaining to your computer is stored in your profile.
The solution lies within your profile. Did you know you had a profile? It’s a folder that stores everything unique to your browser and you can access it by going to the help menu then to “Troubleshooting information”. From there you’ll see a link under Application Basics to show your profile in the Finder.
I can’t pinpoint exactly what it was that I removed that kept Firefox from continuing to crash, but I took a good look at the directory and removed everything that I knew I wasn’t using such as plugins or addons that I had already uninstalled such as Fire Uploader & SEO quake. The result is that Firefox doesn’t crash anymore! I’m thrilled. Here’s the problems I was having so that you can diagnose whether or not this fix will help you: