Okay - you have the latest ver of FF which is stable. I'm thinking you probably have some add-ons that are conflicting.
Under tools there should be an add-ons menu option that when you select it, you should get a list of your add-ons.
This is tedious, but worth the effort - each add-on can be individually disabled. You could disable all of your add-ons and see if it continues to crash. If it doesn't, you can re-enable your add-ons one at a time to see which one causes the problem.
Alternatively, you could uninstall all of your add-ons and see if it crashes. If it doesn't - PM me and I will send you a list of stable add-ons as well as a few links of some great resources that you can get some "pre-configured" add on packages.
In short - my guess is that you probably have one or more of your add-ons that are conflicting with each other and causing it to crash.
Now with that said - I could be completely wrong and the conflict is happening between FF and one of your other apps. That's why I suggest to either disable or uninstall the add-ons and see if FF continues to crash.
On a side note -
www.lifehacker.com has done a number of tests on the various browsers and even though one or the other may edge a bit ahead of FF - it consistently out performs all of the others on average across the broadest range of OSes. BUT - the real test of whether or not a browser is the "best" simply boils down to what you like the most.
If you really like FF, you should check out Thunderbird (email app) as well as OpenOffice (Free Office replacement). They are pretty cool and best of all, they are FREEEEEEEEEEEEEEEE!
Hope that helps a little.