Why is my Firefox freezing/crashing so often?

For the last week or so, it seems like FF is freezing up on me and/or crashing completely every 5 to ten minutes. Almost always when I click on a link, say to go to a new Fluther question or try to open a link in a new tab. Sometimes it just freezes for a minute or 3, and then goes on its merry way. Other times is freezes to the point that I have to force quit with Ctrl/Alt/Delete.

As far as I know, I’ve got the latest version of FF. My OS is Windows XP, if it matters. I’ve followed my own oft-given advice and have cleared my cache multiple times, with no luck. Any advice?