Opera.
-Smaller, faster, and more standards compliant than firefox.
-Built in email and RSS.
-Speed dial, bookmarks, notes, typed history, etc. synched between computers in nearly real time.
-Excellent download manager.
-Well designed and usable sidebar with basically everything you need
-Natively runs greasemonkey scripts without the need for an add-on
-Widgets
-Session manager, as well assession autosave
-Responsive mouse gestures (the gesture extensions in ff are often slow or just don't work all of the time)
And all of this without a single add on.