My big "Duh!" moment in FireFox
FireFox startup performance has been bugging for a long time. FireFox is such a great browser, and the add-ons are so useful, I really can't use anything else for browsing. But sometimes, if I'm in a hurry, I start Safari or (horrors) IE, because I know they will pop open much faster, sometimes 15-20 seconds faster than FireFox.
What bothered me even more was that FF was still slow starting on my super fast new quad-xeon workstation. I mean, what the hell is it doing?
It dawned on me the other day: it was checking for updates for FF and plugins on every startup! Safari and IE don't pay that penalty, since the OS does the checking for them.
So I went into the options, advanced, updates, and turned off all auto checking for updates. Now FireFox starts up in 1 second.