nifty features i've discovered in Opera:
Right Click (hold) + Left Click = back
Left Click (hold) + Right Click = forward
z = back
x = forward
backspace = back
Shift + z = rewind (takes you to first visited page on current URL, max back = 50 pages)
Shift + x = Fast-Forward (opposite of rewind) OR Takes you to the next logical page (might not always work)
middle click on a tab closes it.
middle click on a link opens it in a new window.
Alt + P = the advanced settings menu, which includes the GUI customisation menu. have any icon whereever you want. remove unessesary toolbars.
The Wand DOES work, but the button only works when every item on the page has loaded fully. Ctrl + Enter (return) gives instant Wand
click the bar on the left for the favorites/history menu, then click again to hide it!
Ctrl + Alt + Z = re-open last closed page
In the menu you can set it so that;
A window can have not tabs
A tab does/doesn't have the close button
Opera starts with last open pages / no pages / blank page / homepage.
you can hide/reveal the speedial whenever you want by clicking hide/reveal.
Speedial pages can be opened by pressing Ctrl + Speedial number (Ctrl + 1, etc...)
Ctrl + Tab = Like Alt + Tab in windows, but in that opera window.
Right Click (hold) + Scroll wheel brings up the Ctrl + Tab menu
thats it off the top of my head.
<edit> some more
1 (numpad or numbar) = move one tab to the Left
2 (numpad or numbar) = move one tab to the right
5 (numpad or numbar) = restore (to window within window) tab
6 (numpad or numbar) = 100% page zoom (if you're on any zoom level, press this to return to 100%)
7 (numpad or numbar) = -100% page zoom (so, if you're on 300%, and press 7, you'll be at 200%)
8 (numpad or numbar) = +100% page zoom
9 (numpad or numbar) = -10% page zoom
(minus button) = -10% page zoom
(plus button) = +10% page zoom
F3 (this is awesome) = resume last search (without search window) say you pressed Ctrl + F and searched for "the" and then closed the box, you'd have all the occurences of "the" highloghted. if you click / go to a different page, those will disappear. press F3 and you can jump down from occurence to the next. Try it out!
anyway, i've been using opera since version 7.4 (yes, i did buy it back then)