Quintonil in Mexico City is a nouvelle Mexican restaurant. Brilliant cooking. Pujol is also supposed to be fabulous. Wasn't able to get reservations there.
Fun, high quality meal at Azul Condesa. Rosetta is a nice Italian restaurant -- nice mansion setting but overrated food, I'd say. I have had a couple of great meals at Astrid y Gaston, which is a Peruvian restaurant. I've been to a number of others, including another very good one whose name I can't remember. El Cardenal more traditional but very good.