Lastpass is my favorite add-on, very essential to me Rated 4 out of 5 stars
I love Lastpass and pretty much regard it as totally essential to me.
It allows you to easily have different passwords for every website (so if one web site is broken into and your password discovered it is only that one website that is affected.)
It does an excellent job of generating and recalling passwords.
Some websites use Flashplayer pop-ups for password entry, and this does mean more manual steps in using Lastpass.
If you have more than one account on a website (for example, two hotmail accounts) be sure to edit and select "never autofill" for those accounts.
You'll want to get the latest version of Lastpass so you'll have support for the lastest version of Firefox, and unfortunately at the moment that means going to the lastpass.com website and downloading from there.
The 64-bit downloads include support for 32-bit web browsers.