Another improvement is that FF3.0 remembers if you have re-sized the text size on a particular page. Even better, it renders sites with fill-in areas (such as aa.com) in a much better way than did FF2.x - it keeps the proportions (spacing, etc) of the original page intact, and doesn't allow the enlarged text to bleed into the fill-in form area.

This is a boon to those of us who are age 40+ and have reached the reading glasses stage