Hmmmm I seem to remember it having a big side bar aswell. But meh, I havn't looked at it in a while. I still prefer Firefox because of all the addons and customisation available.
dude, you can turn the sidebar off easily, and by default i believe it only shows when you click in the far left side.... it just shows when you first start opera, one click gone. don't mess wit me nub!!1!
you could have a bug. go to mozillazine.com and search around and chances are theyll have your answer. if they dont then make a topic and youll get help.