I fill out a lot of complicated forms and edit a lot of Wiki pages.  As much as I love Firefox, there are times that it locks up or crashes, which makes me lose all that work.  I just discovered Lazarus, which is a Firefox plugin that stores all your form data as you type.  Now, even if I accidentally close a window/tab, I can only lose a few seconds of work!

Lazarus stores the data in an SQLite file-based database in your profile directory, so it persists even reboots.  It even has the option to store the data encrypted and password-protected, for you privacy nuts out there (/me raises hand).  It’s completely unobtrusive, and does exactly what it says it does.  Give it a try!