I use a lot of tabs in Firefox, and I like to have them open automatically when I open the browser, instead of having to open them manually.

IE7 apparently has this option, but Firefox doesn't have it yet.  Alternatively, there is an add-on you can download called Session Manager that i've been using for a while that takes care of this for you.

Even if Firefox crashes, it automatically saves the sites in the tabs that they were in.  It even has a 'history" of previous sessions you had open, so you could open up tabs previously saved as well.

It doesn't save all of your tabs automatically though, you do need to tweak a setting or two.

First, to download Session Manager, click here to go to the download page.

After it's installed, go into Firefox and click on Tools - Session Manager - Session Manager Options and make the following settings:

Set Previous Browsing Session to load load on startup, and backup the current session at shutdown.  Also, increase the number of older session backups to keep, in case you lost some tabs and need to restore them.

And there you have it, Firefox just got much more useful.