Dj Gudda can you check something for me. In Firefox click on Options then Tools and go here,
Just curious if the "Site Preferences" is checked under Data, and if it is that is why Firefox isn't remembering your zoom settings.
Another reason for asking is that I have two computers both with Firefox on them and using the same profile in both (just copy and pasted the profile from my main computer). Anyway just checked on the second computer for a couple of sites that I have zoomed on my main, and the zoom settings were still there even after moving the profile.
Guess what I am trying to say is that it isn't a problem with Firefox remembering the zoom settings, but a setting in Firefox that is clearing them (or possibly even a 3rd party cleaning utility like ccleaner for example).
P.S. Disable that plugin before testing, don't need ton uninstall it.
Edit: Just tested it and that setting is the one responsible for the zoom settings (among any other things). Pretty sure if you go into the options and uncheck it you won't need that plugin anymore.