You should stay on the beach, not in town. Preferably right on the beach, i.e. beachfront, not across the road. It's worth spending 2-3 hours of your first day driving from hotel to hotel asking for rooms and prices. The further you go (towards the Sian Ka'an Nature Reserve) along route 109, the cheaper and quieter it becomes.
First advise is to rent some kind of a vehicle at least for part of the trip. A car or a scooter/motorbike (if you guys know how to ride it well). 10 days is plenty of time, you can see a lot if you have a car.
Having a vehicle would allow you to be independent from the hotel kitchen (which might be closed, actually, because June is low season), to go to town whenever you like, and to drive to other interesting places.
PLACES TO EAT in the town of Tulum, all of them on the main street:
La Nave (modern Italian) Breakfast and dinner. If you like tomato sauce as much as I do, try his home made salsa de tomate. By the end of our trip the owner would just bring me a small aluminum pot of that sauce and I'd eat it with bread instead of a meal :-)
Don Cafete - nice local Mexican food. Try the ceviche there, it's so good. I found an occasional fly marinated with shrimp, but even that didn't spoil the impression :) It's quite clean for a mexican place, too.
Le Bistro - french breakfast place with a wonderful back yard. It's on a small street off the main road.
My personal favorite local food: La Taqueria (across the street from a chain fast food place "pollo brujo") on Main street close to the intersection with route 109 (which is the road to Tulum beach). It's an afternoon only street vendor. They serve right on the street and close around 3 pm. You can pick fillings for your tacos, some of those tastes you will never ever find in the US. Just be careful not to put something spicy but innocent looking. It can be VERY hot.
I can't recommend anything particularly good on the beach itself, though there are plenty of hotel restaurants. You can go to any one of them. There is an expensive Italian place in a small boutique hotel named something like Margarita. If you want to spend $40 pp for a romantic dinner, I heard the pasta dishes are very good.
So that's food.
As for interesting places, you can go to:
-Coba and Grand Cenote (which is on the way to Coba).
-Tourist attractions such as Akumal (you can swim with turtles and snorkel with beautiful fishes, highly recommended)
-Хel-Ha and/or Yal-Ku.
See how much time you have and how much you want to run around rather than just lie on the beach. All of these places are within a 45 min drive. Also, if you want to spend a couple of hours in a touristy town with souvenirs and restaurants at night, you can go to Playa Del Carmen (go there after Akumal, because Akumal is on the way to Playa). For all of these you need a car.
If you feel adventurous enough for a more serious trip, you can (and probably should) go to Chichen Itza - the pyramids. They are like 1.5-2 hours drive. On the way back you can stop at Valladolid, walk around its small center and eat dinner at a colonial restaurant in the fenced yard on the main square. Don't remember the name, sorry, but it's beautiful and really good.
Also, you can drive the other direction along the beach and go to Sian Kaan, the reserve. If you drive far enough you'll see some amazing nature. There is a natural pool right after the bridge where you can swim both in the pool and the sea. You can also go up the viewing platform in the "Visitors Center". But beware that even though it's quite close, it will take you very long to drive because that road is horrible: bumpy and with potholes.
Если есть время поездить по Юкатану чуть больше, то обязательный минимум это пирамиды Ушмаль (Uxmal), которые намного интереснее Чичен-Итцы, озера Tres Cenotes и город Мерида. Но вообще там еще куча всего интересного, в частности, озеро Laguna Bacalar - очень красивое огромное озеро, где можно провести пару дней в одном из отельчиков на горе со спуском в воду.
Остальные мои заметки о Мексике по тэгу.