Playa del Carmen is where the entertainment, shopping and nightlife is located. We were bummed that we didn't have a hotel reservation here. Next time we visit we will spend a few days in a hotel in this lively area. This is a long street with cobblestones so bring great walking shoes and if you go clubbing bring a bag to carry a cute pair of shoes in, don't wear them or you'll be in blister world for the rest of your trip, trust me this is a long, long street and half the fun of it is walking around from bar to bar.
Fifth avenue is the main drag full of fabulous places to hang out. I don't need to go into detail about any of them because they are all pretty much open air buildings viewable from the streets. There is everything there, high end wine bars, chocolate themed bars and even a few dive sports bars. As you wander down the street don't forget to look up because there are some second story bars. Take some time to look down hallways and explore the courtyards as these have some creative decorations as well.
Take some time to go to the beach and stroll along the sand since there are clubs along the ocean, we went to a few. Just walk along the beach and find one you like. We found one with swings hanging around the bar. We drank at a living room on the sand. They set rattan chairs and loveseats on the sand and decorated small tables with candles. There is a bar with a wooden dance floor, a DJ and colored lights projecting on the sand and makeshift sheer walls.
Make sure to visit this area if you are into the clubbing or fine dining scene. They have a magazine you can pick up which includes a large pull out map. The online website to the magazine is www.la5ta.com/Quinta/View/Flash
It's a little slow and you don't really need advance research but check it out if you need more details.