Sadly Not So Vital Anymore... Rated 3 out of 5 stars
Used to be an addict of this addon on FF2 because of its vital functionality. But as of FF3 (>=v3.08) Firefox ALREADY provides the function of storing "site zoom level" per site, simply try the feature on an "empty" profile. Since NoSquint also stores per site settings in prefs.js, unless you need extra functionality (toolbar and statusbar icons) you won't need NoSquint like you used to be anymore...This review is for a previous version of the add-on (188.8.131.52).
It's true that Firefox 3 stores per-site zoom settings, but it still doesn't allow you to set a default zoom level, which is a trivial but killer feature for a lot of users. Also, NoSquint is much smarter about what it calls a site, and its Exceptions mechanism allows a great deal of flexibility beyond what Firefox 3 has.
Also, the next version of NoSquint will have a per-site color feature, which Firefox lacks natively.