I have been using Firefox 3 since an early beta and was most impressed with the increased speed in OS X. The crucial extensions I need for everyday use have all been updated to work with version 3, so Firefox 2 may well be heading off into the sunset (except for testing, of course).
One of those crucial extensions is Foxmarks, which keeps your bookmarks synchronized and available from anywhere on the Internet. After checking it out, I am now forced to come to terms with my being a digital pack-rat. I found that I have 1,129 bookmarks. And those are just the ones I was keeping in Firefox.