I've stuck to Safari, mostly due to the speed difference in launching and using it compared to Firefox on OS X. It also syncs my bookmarks to my iPhone and other Macs (via MobileMe), and has a decent built in RSS reader. I've also come to like the Top Sites feature, as I can tell at a glance what web pages in my favorites have updated content. Lets see, I also like the ability to enlarge form text boxes (like this posting box), and the built in web tools for inspecting elements on a page and tracking down performance issues.

It's also been nice to have the 64bit version running on Snow Leopard, as it also adds out of process plugins. This means when a plugin crashes, my browser doesn't. Safari also doesn't load plugins until the tab is active, so if I open a lot of links in new tabs to read later, one of them won't randomly start playing some random video or audio content. Lastly, ClickToFlash and HTML5 support has been two big things for me recently.

That about covers it for me. Been pretty happy with Safari over the years. Prior to it, Firefox was my main browser, going back to the Firebird beta days.