Not username. That would make it harder to know when you're having a back-and-forth, and that changes the nature of the discussion. Removing points would be a good idea, though - is there any advantage to having that visible beforehand?
knowing you're having a back and forth with the same person is one cause of long flame wars. not knowing who you're talking to keeps things less emotional and more polite. i think.
the advantage of seeing points is the same as seeing orange usernames. it allows people to decide which comments they want to read.
