Opera Software's "alternative" web browser, aptly named Opera, hit version 9.10 yesterday. The only new feature of note is the anti-phishing filter they've added, but this release also includes bug fixes aplenty. Opera is still free (although @29 USD will buy you "premium support" via email), it's Universal Binary and you'll need OS X 10.3.9 or later to check it out.
Opera has never "felt" right to me on the Mac, so I rarely turn to it, although I do keep a copy handy in my Apps folder for special occasions. That shouldn't and won't stop you from using it, though. For what it's worth, I do like the Opera Mini browser on my Blackberry.