Firefox got really disappointing recently, but I'm not sure where users will head if they decide to change. I ended up on Chrome (has the addons I liked on FF, it's quicker and has no memory issues).

Opera is still an excellent browser.. IE 9 is pretty good too..

I do wonder whether, with IE having improved as much as it has, the migration from Windows 7 to 8 will have much of an effect. If IE 10 is at all better than 9 then it'll give good reason not to download a 3rd party browser again (unless you really like addons).