Was in Playa Del Carmen a couple of months ago. Stayed at one of the many little family run hotels - a delight ! 100 yards from beach, 20 yards from dive center. There are many smaller, good value hotels and several small 'boutique' hotels that are truly fabulous, very modern rooms etc - but US 5* prices !

1) Playa Del Carmen took full hit on recent hurricane; but it is a neat little town. Kinda touristy and lots of tourist crap in the daytime. But by night; there are some good bars, excellent restuarants, GOOD live music too. Its smallish and not the vast hotel-plaza of Cancun and theres plenty of well-off Mexicans enjoying the more classy places. Personally, 'full service resorts' make me clostrophobic; so the place suited me just fine.

2) Day trip to Cozumel is easy for some of the best clear water diving (check on post hurriacane situ) around. I'm BSAC instructor/PADI OWSI (not my profession !) and PM me if you want any more diving info.
If you are into diving, a cenote dive is not to be missed.

3) Chichen Itza is a must. Its a full day trip by bus. Tours tend to be cheap but insist on taking you to shops/'free' breakfast at timeshare sales place enroute in the hope you'll buy stuff and you end up with only 2 hrs at the pyramids. If you have 4 people; bargain hard and just rent a private taxi for the day to enjoy your own schedule. Works out at same cost but with great flexibility.

4) Taxis are everywhere; but know that the rates of taxis at the 'resorts' are far higher than a little friendly bargaining at the local taxi hang out will achieve.

5) Many 'open' wi-fi spots in Playa del Carmen - so you can keep in touch with X5World :-). I used 'Skype' on my powerbook to talk for free to US and UK.

Enjoy,

PC