I think we're going to see FireFox go the way of Opera in the next few years.

They had a great start, and forced Microsoft to release IE7, but since then they've just sort of coasted along. MS came out with IE8, which turned out to be a pretty good browser. Then Google came out with Chrome, which redefined what a browser is supposed to be like.

So now we have FireFox still taking 30 seconds to fire up and basically functioning like a poor version of IE8 (but with plugins), while IE9 is coming out looking exactly like a Chrome clone and Chrome is sprinting off into the distance (yet still firing up in 3 seconds).

FF just seems to lose a bit more relevance every year.