It must be middle age, but my tryst with FireFox was only a brief affair. And while I can't say I have any regrets, I'm very happy to be back in the metaphorical arms of my first love, Safari.
The number one reason? Speed. Safari is simply the fastest browser for Mac that I've tried. FireFox doesn't even come close. Sure, FF has all those extensions, but I don't use that stuff. And Safari is just prettier than FireFox. Again, the latter has extensions, but for deep-down, natural UI loveliness, Safari is my gal.
OK, I'll stop with the hokey metaphor... One thing that the brief switch did do, however, was to make NetNewsWire a permanent fixture in my computing experience. I was using Safari's RSS reader, but after trying out NNW for a few weeks, I can't go back. With NNW, it's so easy to sift through hundreds of feeds for the few readable nuggets. In fact, NNW is almost a browser itself, and surely browsers of the future will have to include a NNW-like interface.
The new Flock browser, just released in beta, also implements RSS, and while it does a better job than Safari, it has a ways to go before it achieves NNW's usefulness. But Flock has the right idea, I think, which is to start incorporating Web 2.0 features such as Flickr and blogging into the browser. I have yet to try out the blogging feature, but again, it appears to be a step in the right direction. (BTW, if anyone can tell me how to put folders into Flock's bookmarks toolbar, I'd be grateful. There must be a way to do this, but I can't for the life of me figure it out.)
Oddly enough, the reason that motivated my short-lasted defection to FireFox-- Quicksilver's Google Calendar module--turned out to be a bit of a bust as far as my workflow is concerned. I didn't use it once, and now that I'm back to Safari, I think it will be more useful to use QS's iCal module instead, which doesn't work quite as well as the Gcal module, but gets the job done.