We generally try to limit the number of extensions we install for security, performance, and because we use a lot of different systems. That’s not to say there aren’t a lot of interesting addons out there and Mozilla has recently announced the winners of their Extend Firefox 3 Contest. Lifehacker has a full rundown of each of the winners. Nothing really stands out in our eyes (although we might try Last.fm’s toolbar).

The three extensions we always end up installing are Firebug, Greasemonkey, and Flashblock. What are yours?