While the beta of IE 7 looked miles ahead of IE 6, i don't trust Microsoft at all. Firefox is a stable, easy handling browser with many capabilities perfected that IE 7 has done a slapshot job of copying.
The RealPlayer browser? Does that even count?
Opera. It's fine. It's up to par with being a complete web browser. That's about it.
The others...well, not good. The major one being the now reborn Netscape which has an excellent GUI but is horrible otherwise. It can emulate IE or Firefox. If you want a browser to do that, get IE or Firefox!
My choice (if you haven't figured it out): Firefox