Well, if you haven't, lemme quickly update you.
Since the release of Google Chrome, everyone's been trying to compete! It was fast, it took such little space, and Opera and Firefox have somehow ended up along the same lines.
See the screenshot above? The only difference I really see between Opera 10.6 and Firefox 4 Beta 6 is the colors of the 'shortcut-menu' at the top left corner. It's painful to see, it really is. Worst off is that Opera did it first! Anyway, when maximized at least Opera's one goes to become like the first tab and so takes up less space (compared to Chrome it's exactly the same size), but Firefox's stays up there which makes it take too much space!