first off there is http://www.flock.com/
This is an up and coming browser. It is built around the firefox core. It is not just a plug in but a complete suite. It is designed for taking advantage of the social aspects of web 2.0. it has bookmarks based off tags instead of folders. It is designed to blog intergrated and rss intergrated.
An online shared resource word processor. THis is uber cool and I may load up a lot of my writing projects here.
A really good ajax based home page. Completely customizable and very useful.