If you want your tabs to open permanently. Go to Tools -> Options -> General. In the start up, choose 'Show my windows and Tabs from Last time' in the drop down menu.
Hmm, never realized. I've had it enabled by default since Firefox 4, oh god... Now I'm using Aurora, though :I
/b
Well fade uses opera and its main feature that i liked is that it kept the tabs open after you quit your browser, so i could just quit firefox and not have to remember what website i was looking at and all that stuff, other than that opera and my firefox are pretty much the same now due to plugins and such.