I usually stay at the Maya Bric [
Hotel Maya Bric Playa del Carmen European Run Budget Hotel in Central Playa del Carmen Mexico] Yes, it is spartan, but it has a/c and a nice lounge area with tables and chairs. They will put a little TV in your room if you ask nicely for it- they always put one in our room for the kiddies. Plus, there's free Internet access in the lobby. You can't beat the price and location.
I also like the Maya Turquesa.[
Hotels Playa del Carmen, Mexico: Maya Turquesa Hotel]. It's just a couple blocks west of 5th Ave. A little further from the beach than the former, but not too far. It's a fairly new place and they have suites with full kitchen on the 2nd floor.