High season for hotels in Natal is December through February, and then again in July when Brazilians take their winter holidays. Outside of this period it is possible to obtain substantial discounts. Remember also that in Brazil you can often get a better rate if you book through a travel agent.
Ponta Negra -- Ponta Negra is the most popular beach within the city limits. It's wide, clean, and busy, with good waves for surfing. A pleasant waterfront walkway runs along the beach, past a number of beachside restaurants and barracas. In the past couple of years many of the city's better restaurants have opened up branches in the area, and several new cafes, bars, and nightclubs have set up shop. All this means that if you're going to stay within the Natal city limits, Ponta Negra is really your best option. The few sights worth visiting in downtown Natal are only a 15-minute cab ride or a 30- to 40-minute trip by city bus away.
Via Costeira -- The Via Costeira parkway looks like a lovely place for a hotel (and it is) but there are a couple of drawbacks. Though you get outstanding views and unmatched isolation, the ocean is rougher, and there is nothing within walking distance, so you're looking at a cab ride any time you want to leave the hotel.