I know it’s still in beta, but Firefox 3 is looking really really nice.

Really fast, funky drop-down preview/autocomplete thingy in the location bar, nice styling and look and feel. Lovely.

Give it a whirl from Mozilla: http://www.mozilla.com/en-US/firefox/all-beta.html

PS It seems to co-exist fairly happily with FireFox 2 under Windows.