Rarely available prewar classic seven in top Carnegie Hill building.   With open views, the sun-drenched southern exposure welcomes you with gorgeous light all day.     The double entry leads into a large living room which has a beautiful wood-burning fireplace and distinctive prewar detail, including high ceilings, lovely moldings and handsome hardwood floors. The formal dining room is tailor-made for entertaining - it is open to the living room, and you can enjoy magical evenings dining with a view of the fire. The apartment is wired for music throughout.   There is a butler's pantry with a wine rack and cooler, plus a beautifully designed windowed eat-in kitchen with a comfortable banquette. The appliances are top of the line and there is excellent storage space.   This special three bedroom apartment has an excellent layout with abundant closets.   The master bedroom is huge and has a beautiful en suite bathroom. The two other bedrooms are large and beautifully proportioned; the third bedroom is currently configured as a charming library. There is a maid's room with a washer dryer, located in the former windowed bath which could easily be reinstated. The apartment is fully air conditioned and has a storage bin.  This building has a gym and a playroom, and is located in the heart of Carnegie Hill. Everything you could need or want is just steps from your front door - Central Park, the Reservoir, Museum Mile, shops, excellent restaurants, and the best bookstore in New York City.