In Centro Histórico you will find a lot of cafés, restaurants and bars with a view but non of them can compare with the one of El Mayor. This place is located on the top floor of Librería Porrúa. From there you will see, right next to you, Templo Mayor, Palacio del Marqués del Apartado and Palacio de la Autonomía. A little bit further you will discern the cathedral and the zócalo, and even Torre Latinoamericana.
At El Mayor you will find what every café offers: sandwiches and coffee. For $100 MXN you can get a panini, a glass of fruit-flavored water, a cup of coffee and a cookie. With the view and the nice, calmed environment you will be enjoying, I find this to be one of the best deals in the city.
Right next to the café, the restaurant offers delicious Mexican food so, if you are not on a budget, you should go there and try the chile relleno – a chile stuffed with chicharrón (pork) and wrapped with tortilla dough. No matter what you choose, spending a while at El Mayor, with its incredible view, is always a good idea.