There’s a Firefox extension called Scrapbook that’s an absolute lifesaver for research — it lets you grab web pages for offline use as usual, and then gives you some nice editing options like highlighting and commenting. It can also smush the bits and pieces you select into one big page suitable for printing.

There’s also Session Saver, for when Firefox craps out on you when you have a million very important tabs going.

And ForecastFox, for when you’re too lazy to actually look out the window before you head to class.

Mozilla Calendar, which I’ve since replaced with Hipcal because of the better support for todo lists, but a good little PIM in its own right.

And last but not least, PDF Downloader, for those endless lists of sample exams. I use this in conjunction with Foxit Reader (no relation to Firefox), which is a very nice lightweight PDF viewer. What can I say? I’m impatient.