There are two possibles meanings of Cancun, according to the Mayan language, the first translation is “nest of snakes or pot.” The second version (and less accepted) is “place of the gold snake”.
Peak season in Cancun tends to run from December to April. Prices in both airfare and hotel increase dramatically during these times, while dropping in the summer and early autumn months.
The Cancun hotel zone is almost entirely built around the tourist industry. It abounds with all-inclusive resort hotels. Stay there if you don't mind spending your vacation with many other tourists. Most tourists are primarily from English-speaking North America and there are also many tourists from Europe, but many tourists also come to Cancun from the rest of Mexico.
Downtown Cancun, especially once you get away from the ADO bus station and nearby hostels and hotels, is where most residents live. There are many restaurants (La Parrilla, Los Pericos, Los Arcos, El Timtnhehdon de Cancun, Va que Va; all of them are really good restaurants, and the best much cheaper than Hotel Zone, and Mexican cousin), shopping centres (Plaza Las Americas, Plaza la Isla in Hotel Zone, Plaza Outlet), markets (Mercado 28 y 23) and clubs in the downtown area that you can visit during your stay (Cocobongo, Dady'O, Palazzo, Mandala).
Those mostly seeking beaches and scuba diving, or who are a bit adventurous, can easily find rooms on equally beautiful and less crowded beaches along the coast just an hour or two south of Cancun. Some Spanish language skills may aid in finding better deals. You can rent a car, or take the bus to Puerto Morelos (about 20min) or Tulum (1h). Playa del Carmen (45min, MXN198) is between the two, but caters to the all-inclusive crowd. Taxis are also available.