don't know about mouse 1 and mouse 2 but mouse 4 and mouse 5 seem to work reasonably well in Firefox Opera and IE
just downloaded firefox 3. SO MUCH BETTER THAN FF2. noticeably more responsive. don't quite like the UI as much but that's minor. lower system demands too which is nice. not a major concern for me but still nice.
xlink, I know they work in firefox etc. But I justlove the feature of holding down mouse 2 and pressing mouse 1 to go back, or holding down mouse 1 and press mouse 2 to go forward.
there IS a firefox extension that does that I used to have it. then i got a 5 button mouse and stopped caring and I can't go back now.
FF rox! I use IE only when I am too lazy to input my login for hotmail (clicking the inbox icon on live messenger open the inbox in IE browser even when my default has been set to FF). I like FF because it doesn't have those troublesome top bars popping out whenever there's ActiveX content. FF also has a valuable add on that I highly recommend: Adblock plus. It allows users to block ads and other content on pages. Another thing is, I open 70 tabs on FF and my pc still runs smoothly but if I open more than 10 tabs on IE, my pc starts to lag.