Yeah, I love Opera too. I am stunned how 7.50beta can be even faster. I tried Mozilla (which is great too) for a while and went back to Opera after about a day because of all the little considerations that Opera has in the interaction side of things.
For example, in Opera closing a tab returns you to the PARENT tab, in Mozilla (version I tried) you go to the next tab TO THE LEFT on the bar meaning you have to navigate and select the parent one (EVERY time). In Opera you can open in same window, open in new window etc. all from a right-click, and mouse gestures are great, you can navigate and hardly ever move the mouse. Mozilla was nice but too many two or three click actions, or right-across-page navigations that were faster in Opera.