Over at Mozilla Labs, they have announced what they call the Extend Firefox winners, which list add-ons voted as the best by a team of judges. Some of the add-ons are still under development but as Mozilla Labs states are still powerful news tools for Firefox 3 users to take advantage of. Some of the new prize winners include:
GUI prototyping and diagramming that everyone can use.
The Pencil Project’s unique mission is to extend Firefox 3 to an opensource tool for making diagrams and GUI prototyping that everyone can use. Pencil makes uses of the SVG support in Firefox 3 to implement all the shape rendering and scripting.
One click bookmark tagging
This add-ons adds a set of icons to the quick bookmarks, allowing you to quickly add tags to your bookmarks by clicking on each icon.
Automatic bookmark tagging
HandyTag simply providing a complete set of most relevant keywords in the bookmark’s edition panel. These keywords are retrieved from many different sources.
There are many other award winning add-ons that came in as runner up, but also may be useful to you. May I recommend you take a look at the Mozilla Lab web site for additional information. There appears to be something for everyone.