I like Firefox and don't see any real reason to switch away from it currently. The things I like going for it are tabbed viewing, the show windows and tabs from last time feature, it's ease of use for bookmarking and backing up/restoring saved bookmarks should you do a OS reinstall, overall stability, performance, and security, and vast amount of plugins particularly Adblock.
With all that said I've read good things about Chrome and Opera as well. Really just about any web browser would be better than IE.