Since the Palais Maeterlinck has closed, the Nice hotel scene is pretty limited. The most luxurious option with a location right on the Promenade is the clever Palais de la Mediterranee, with the historic facade kept from the old building fronting an all-new hotel.
As far as restaurants, stay away from the tourist lists! The restaurants are overhyped and quite underwhelming! For a most memorable meal, head to Millesime 82, Luc Salsedo, or Flaveur.