Tulum, Mexico
Tulum was jokes, was so funny, everyday was memorable. Yeah, the ruins are impressive and the beach is nice, you can scooba\snorkal in reef caves - but who gives a s***. What made Tulum good was the people, I got drunk and stoned every night with literally some of the best people i have met out here. There was even a friendly Canadian girl ;).
I would recommend coming to Tulum for 2 days max, after that you have seen everything. However, if you meet good people ...