Dolphin HD for me. Plays videos, reflows text, does pinch and zoom.
But the killer feature for me are the gestures. I can load web pages in a split second with gestures, go to the bottom or top of the screen with gestures, and slide between tabs with gestures (this is a new feature). I can navigate to the previous or next screen, close tabs, open new tabs, go to bookmarks, reload the page -- probably something like 80 % of the commands in Dolphin are done with gestures.
I did flop the gesture OSD to the right side since the transparency was interfering with readability on the left, and I disabled the swiping to access bookmarks because it's not tight enough for me.
But the gestures save me a ton of time.