I am not convinced about the stability of 64 bit FF. Even with no add-ons, stability is poor. Hope it gets fixed as more users start using it and more crash data shows up.
I've been using 64-bit Firefox Nightly for some time with few crashes. The last time it crashed, I was politely asked (by the Mozilla developers) to do this:
1. restart Firefox, enter 'about:crashes' in the URL bar
2. find the report ID that corresponds to the crash
3. submit it as part of a bug report to Mozilla's Bugzilla
My crash problem was diagnosed within a day and fixed.
I started using 64-bit Firefox on Windows about a year ago, and carried over all my add-ons. It crashes way less than my 32-bit Firefox, which tends to die after allocating 1.8 GB of memory. What makes you say 64-bit FF is more unstable for you?
1. restart Firefox, enter 'about:crashes' in the URL bar
2. find the report ID that corresponds to the crash
3. submit it as part of a bug report to Mozilla's Bugzilla
My crash problem was diagnosed within a day and fixed.