If you run Firefox, you absolutely positively need to stop and go install Lazarus: Form Recovery.
Earlier today, a client asked me about a ticket that I had filed with their hosting provider, and if I would mind filing it again. Of course I wouldn't mind. And of course, I didn't have a copy of the text I had written in the ticket. But, good old Lazarus Form Recovery did. I just brought up the page with form, right mouse clicked on form somewhere and selected "Recover Form."
That's what makes Lazarus so cool - it automatically saves every form you submit (knowing to skip saving credit cards and passwords), so if you crash your browser or need to submit the form again you can.
No doubt, this will get built into all browsers eventually, it's just too handy to not have.