Just switched to FireFox this week on my Mac at work (from Safari) and my two PCs at home (from IE). Love, love, LOVE it. What extensions do you guys recommend right now? So far I've gotten:
Foxmarks - My favorite add-on so far. Allows you to keep bookmarks synchronized between two or more computers. Now I can use the same bookmarks at work, on my laptop while watching TV, and in my home office. When I add something, it's available at all points. Awesome.
Gmail Space - Lets you use your extra Gmail space as a kind of Web hard drive. Great way to shift large files between multiple computers.
WeatherBug - Really nice integration of WeatherBug, my favorite weather app, into FireFox.
Download Status Bar - Downloads are displayed and managed on the status bar, rather than in a separate window.