Tab Mix Plus is a Firefox extension, providing a veritable boatload of tab features and also a session manager. You can rearrange tabs, protect tabs from being closed, unclose tabs, have a loading bar for each tab show up in its little name spot, and my favorite feature of all: Making multiple rows of tabs! When I max out my tabs in Firefox, what usually happens is that they extend off the side of the window, making it very tricky to work nicely with them. Now, they wrap around and make a second row. Whoo hoo!
I don’t have many problems with Firefox stability, but I faked a crash to check out the crash helper thing. When I restarted Firefox, Tab Mix Plus came up and asked if I wanted to restore from the crashed session.
Here’s to you, Tab Mix Plus.