Internet Explorer 8 beta & FireFox 3.0 beta 4
I still prefer Internet Explorer. It launches a many times faster than FireFox. That may of course be because Internet Explorer only has the Google Toolbar but FireFox has ~10 plugins loaded that I use every day...
What I am waiting for is a real mobile web browser. The iPhone web browser is light-years ahead of everyone else so it is no wonder that the competitors are all scrambling to implement something "similar". It looks like most companies are going the Apple way and basing their new mobile browser on Web Kit, apart from Microsoft which I assume will use the Internet Explorer code base. I don't really care if the code base is FireFox, Web Kit., Opera or IE as long as it is can be used for really browsing the web on a mobile device.