Firefox.... Firebird Renamed
Well they just released Firebird v0.8, well not exactly it is now been renamed to Firefox 0.8. But anyways if you aren't using it as your primary browser then I suggest that you check it out. I have been using it for a while now and I love it, I can't get enough of the tabbed-browsing and its clean feel.
I use it along with Sitebar, which is a very cool online bookmark manager, that I load up in the sidebar of Firefox. (What I like about sitebar is that it is open source so I am hosting it myself on my webserver and when every I go anywhere I can load my bookmarks in the sidebar or search bar (for ie) and I have all of my bookmarks, really awesome)