Chichen Itza
Word is that you still can’t climb El Castillo, and that you have to get “permission” to climb up the interior pyramid to the temple inside. I’m not sure yet what this entails–real, signed papers or just a special, separate ticket–so you may want to ask at the main desk before you go in.
I’ve also been warned that the situation with the crafts vendors is getting a little out of hand–lots of pestering.
And of course you’ve heard that Chichen Itza is a “New Wonder of the World.” All I can think is: Yikes. Crowds-a-million. On the other hand, more people will help divert all the crafts vendors!
I don’t editorialize much on this site (for that, see Roving Gastronome), but as a tourist, I get grumpy at the thought of mobs of vendors and crowds. As someone who works in the tourism industry, though, I can see that people need to make a living somehow. As long as you go to Chichen Itza (or Cancun, or the Pyramids in Cairo, or wherever) knowing you are not going to have a silent, solitary moment of communing with the ancients, then you will have a much better experience. You have to appreciate the modern phenomena as much as the ancient ones.
Still, makes Ek-Balam and, say, the Chenes sites over by Campeche so much more appealing.