I use FF too for my daily surfing and stuff. But Opera still has the best bookmark system I think, and I need a second browser for my frivolous female image surfing. I usually leave have 30+ tabs open when I shut it off too, and Opera preserves those without even needing a plugin.
As for upgrading Opera, no thanks. It keeps getting clunkier. I wish I could easily downgrade to an earlier version in fact. But Web standards keep evolving, so that is unfeasible.
How do you guys get by using just one browser? I use four. (IE occasionally, and Kmeleon for quick starts - no saving tabs rule I enforce on myself.)
Maybe I should use Windows profiles instead?