I generate maybe 60 tabs a day, and finally came to the conclusion that I was using tabs incorrectly. Tree Style Tabs is great, but I found that I was using tabs as combined bookmarks + todo list. So I wrote a Firefox addon that pops up a sidebar every morning and steps through every tab prompting me to either close it or save it as a bookmark. (with tags) It has definitely helped with this vague uneasy feeling I have about occasionally restarting Firefox and having to automatically reopen hundreds of tabs, most of which could have long ago been garbage collected.