I like Opera but keep going back to IE because my mouse wheel does not work with Opera. Try without it sometime and it is sooo frustrating!
What versions of stuff are you using 'cos mine works fine with wheel. I am XP (Home) with Opera 7.11
I found out that the mouse wheel in Opera works only if the cursor is in the web page and NOT in the various toolbars.
Which is exactly the same as the IE 5 that I am curretnyl using (at work)