Well cool. I tried Opera and I like it, very neat looking and more functionality to play with ... I think - it crashed on setup a few times, but it looks way cool.
And I finally tried Firebird, Randy mentioned it above, and I've been curious so I gave it a go. It is really cool - in that it is _streamlined_ way more that Moz 1.4 w/ very cool themes for it. I Highly recommend looking at Firebird for you 'Tab' people. The 'install' is basically just un(g)zipping, running a small reg update - run mozillafirebird.exe -p. (there is an installer ver too)
Firebird has been very stable for me so far. (Don't receommend installing it 'over' your mozilla install...)