It all depends on what you are interested, we stayed in Playa del Carmen which is about 15 minutes away last year and we are returning this year in September.
If you haven't been before it is a crime to go and not see Chichen Itza, it's about 3 1/2 hours on a coach or you can get a plane from the small airstrip in Playa del Carmen.
The ruins at Tulum are about 1 hours travel away with the Xel-ha eco-park close by, worth doing both on the same trip.
http://www.xel-ha.com/
Xcaret is another park which you definitely need a full day to fully enjoy including the spectacular evening show, about 10 minutes from Playa del Carmen
http://www.xcaret.com/
If you check on the many sites for the general area you will find that there are several local tour companies who do excursions which are also cheaper than the 'big' operators.