In Havana my top recommendation is the Saratoga which was centrally located at Paseo del Prado #603. The hotel was an extremely attractive, top-end five star hotel across from the Capitolio (or Capitol building). It has been totally restored with large rooms, attractive bathrooms, gym, business center with internet, cable TV including CNN, restaurant and roof top bar. Since you are spending time in a city where the majority of the buildings are rather shabby, it is nice to come back to a great room and comfortable bed. You can also change money at the hotel.
Another option would be the historic Hotel Nacional de Cuba which opened in 1930. It is located in the Vedado neighborhood on a hill overlooking the ocean. It has great views of the Havana Harbor, the seawall and the city. If you don’t stay there, at least go for lunch or a drink overlooking the water. I stayed there on my second trip to Havana. It is great staying in such an historic hotel, but the rooms are somewhat dated and there are many tour groups staying there in the busy season. They do have a business center with WiFi which can be accessed in the rooms as well. They have a number of bars and restaurants. I really loved the show at the Cabaret Parisien which is located in the showroom off of the lobby.
NH Capri Hotel in Vedado: Located in the central area of the Vedado neighborhood, this is a 220 room hotel that is more contemporary than most in town since it was remodeled in 2014. It has money exchange facilities, two restaurants, three bars, wireless internet, pool, gym and more. Calle 21 entre Calle N y O.
Good friends in Toronto just told me that the Hotel Santa Isabel is a great hotel in Havana on the Plaza de Armas.
For Hemingway fans, you might try the Hotel Ambos Mundos where he stayed and wrote For Whom the Bell Tolls in the 1930’s. The hotel has a popular rooftop bar and the elevators and lobby can be crowded with tourists. If you want a quiet spot, this may not be the place for you. The location is excellent