Firefox 2.0 launched a couple of days ago. Please tell me you are using this browser! It has so many features compared to Internet Explorer it blows me away. I've been a dedicated Netscape/Mozilla/Firefox user since the 90's, and with good reason: for the power user, this browser is unrivaled.
2.0 is more a marketing release than one including major new features. One feature I like though -- a keyboard shortcut for undoing closed tabs:
Ctrl-Shift-T (Windows) or Cmd-Shift-T (Mac)
Enjoy. Download here