Aside from furnishings like benches, plants, standing ashtrays, velvet ropes, etc., I can't think of much to add or change that you haven't already mentioned. Keeping the set general-purpose limits one's options. A chandelier might be appropriate, though it could just as easily be inserted as a separate prop. I'd suggest some light fixtures, anyway. A kiosk could make a good alternative to the 'table/fountain/dunno-yet' item; you know, one of those illuminated map-things that says "You are here."