Really? I have to restart Firefox 3 much more often than I ever restarted Firefox 2. I routinely left Firefox 2 running for a month at a time with 100+ tabs spread across several open windows in different workspaces. Firefox 3 only lasts for about a week in a similar situation. Chrome uses more memory per tab, so 100+ tabs isn't feasible with it. (Maybe it is now, I haven't tried recently)