Personally, I feel as though a minimal UI with a black and white color motif would be best. I'm not a fan of mini maps, big chat boxes and quest logs taken up space on my screen.

From what we've seen and heard I believe the UI is incredibly minimal and actually disappears when not in combat so it's not pointlessly cluttering up the screen.

I couldn't be happier about their design philosophy re the UI, i.e. that players should be playing the game, not the UI.