An Adobe PDF just crashed my FireFox. I had about 12 windows/tabs open at the time. I was almost peeved (but managing to keep my cool). I then went to re-open FireFox 2.0 and was presented with the option restore my former session. Not having done this before I was not sure what would happen. To my most excellent suprise, all of my windows/tabs were reopened (except for the one that crashed the app) exactly as I had them before!
Wicked sweeeeeeet! Bravo to FireFox. As if I needed any more reasons to make it my primary browser.