Google Browser Sync

Google Browser Sync for Firefox is an extension that continuously synchronizes your browser settings – including bookmarks, history, persistent cookies, and saved passwords – across your computers. It also allows you to restore open tabs and windows across different machines and browser sessions.

Interesting idea, sounds like it could be useful in some instances, but I have major issues with trusting Google with all of my cookies, saved passwords, etc … maybe it’s for you though, it’s just not for me.

Flock

Flock is a free web browser that makes it easier than ever to share photos, stay up-to-date with news from your favorite sites, and search the Web.

A brand new public release is now available, just a brief FYI for people considering trying this: some Firefox extensions are compatible, most are not so there is no guarantee that your favorite extension will work with Flock.