I just found an interesting feature in Firefox 2. If you have an open tab, then close it, you can right-click the tabs and choose 'Undo Close Tab' and the banished tab will return.
Jim Priest, who turned me on to the Microsoft Update Reboot Fix points out that the following key combos work:
CTRL+T = new tab
CTRL+SHIFT+T = restore last closed tab
I've use CTRL+T countless times. It never dawned on me to try CTRL+SHIFT+T. Thanks again Jim!