It depends on your own tastes, of course, but I think for a lot of people BG2 visuals beat most later games. They represent the apex of that particular generation of graphics, with gorgeous 2D locations still leaving a lot for the imagination to do. However, if Bioware had decided to stick with that generation and not move on to 3D, they would have gone bust by now. Got to move with the times, eh?
The BG and IWD games had beautiful visuals. Better looking than most games since then.