I recommend staying on Isla Mujeres which is just off of Cancun. Here's some reasons why:
- Safe!
- It's easy to reach via air-conditioned ferry. We book a private airport to ferry transport online (very reasonable price).
- Lodging options are excellent: condos right on North Beach; luxury resorts; casas that can be rented from homeaway.com or vrbo.com; small boutique hotel like Casa de los Suenos, etc.
- No rental cars: visitors use the inexpensive taxis or rent golf carts by the day or the week (we rented by the week)
- Restaurants and shopping: Excellent!
- Day trips: You can book day trips for snorkeling, diving, etc.

There are also numerous large resorts all along the Maya Riviera which extends from Cancun to Tulum if you prefer the resort atmosphere. If you did decide to stay at one, I recommend booking a day trip to one of the Mayan ruins and also to a cenote.