A MUST have Rated 5 out of 5 stars
This is one of the 3 must have extensions for Firefox (along with tab mix plus and mr tech toolkit). I know that Mozilla is working on off-line browsing in FF 3.6 (or was it FF 4.0), but you can have all the off-line browsing you need with Scrapbook right now in FF 3.0.
I read many of the reviews bor Scrapbook below, many of which are suggesting useful "new" features. The interesting thing is that all the suggested "new" features already exist in Scrapbook, and have been in since long before it got to version 1.3. So my suggestion to new users is - go to the extension's home page and read the user manual - you will find that Scrapbook has some amzaing features.
Thank you Gomita!