Staying in DF
Highly recommend a visit to Mexico City - there is so much to see and do here. The metro makes it very easy to get around, although crowded at times it doesn't feel unsafe. Many museums are free to visit on a Sunday too. The artesan craft market is a must see, best place to shop for mexican crafts - and make sure you visit Teotihuacan, the ancient site about 1hr out of the city.
Insider Tip:If you like street art, step out of the norm and pay a visit to the Museo del Jugete (Toy Museum) - there is lots of beautiful street art to be seen in the area and the museum itself is quirky and fun!