If you were to switch, chrome works fast but, personally, I am not to trusting of google. No real reason.
Firefox is always good and you can easily import your IE stuff into it.
Opera, some like it, I tried it but meh.
Safari is ok but better on mac.
personally, I use firefox 4, it is not beta anymore and is pretty quick and stable. Plus all sorts of add ons such as mouse gestures.