Speaking of browsers, there's also Camino, a Mac OS X-specific Mozilla-based browser. Had used it for a while, a while ago, before switching to Firefox. Trying it again right now. It does have access to Mac OS X Services, which is quite an important feature for me, but it doesn't seem to support the global Mac OS X spell-checker, which is almost a deal-breaker for me. In fact, these two features are the ones that Firefox itself really should have.
Camino also seems quite slow in WordPress. Kept getting “unresponsive script” warnings and even typing in this box seems quite slow. No idea why but it makes the experience much less pleasurable.
So, at this point my preferences are: Flock, Firefox, Safari, Camino, and Opera. Other browsers (iCab, IE, Netscape, lynx, OmniWeb…) could be useful at times, but they add less to my browsing pleasure than those five first browsers.
Actually, one of my main reasons to switch to Mozilla browsers has been because of my switch to cross-platform environments, especially since getting my eMachines since the very end of 2005. Been using my old iBook (now my wife's) very intensively since early May and have been mostly using Firefox (and now Flock) on the iBook too. Transfering my profile from one machine to next was relatively painless and the consistency of experience from having the same history really did help. Now with the Google Browser Sync extension, the transition back to Firefox/Flock on my eMachines will be even easier. (Been using the extension on both my iBook and the desktop Dell running XP, at work. Works flawlessly and is exactly the type of feature which makes so much sense that you wonder why it didn't exist before).
The most interesting thing about Firefox is the set of extensions made for it. Been using Gomita's Scrapbook Extension extensively (thanks to a del.icio.us link from fellow linguistic anthropologist and blogger Kerim Friedman). It really helps to archive many different things and the archives can easily be transfered from one computer to another. Scrapbook has other powerful features including extensive highlighting functionalities. The Session Manager extension is also a must for Mozilla browsers, although its functionalities clash with the browser sync, to a certain extent (at least, the part about restoring pages).
If only Firefox and Flock had spell as you type!