Can I ask you why do you leave all those tabs opened all the time? When I get to 20-25 I go mad and start frantically close almost all of them. I really depend on Awesome Bar to reopen sites though (but I like it)
They are things I want to revisit and I found that putting in a "To Sort" bookmark folder doesn't cause me to revisit. I am forced to eventually revisit and decide if I still need it or not. But I don't go to 300 tabs, I usually purge around 100 or less.
