Holiday Recomendations. (Mexico City)

Hello everyone!

I am in need of some good holiday recomendations! My boyfriend and I are planning on staying in Mexico over Christmas and New Years and want to take advantage of the holidays to travel and explore!

I am not a big fan of the big luxury hotels (although very comfortable - you could be anywhere in the world when you stay there!) and do not want to go on any group tours.

If anyone can recomend any town, cities that are a 'must' to go to, or even share any experiences that would be brilliant! Also, I love the beach and the coast - so if anyone knows of any small family run hotels or comfortable shacks on the beach...please share!

Thanks in advanced for any advise!
Best,
Alex