So, a few weeks ago I posted a question about food in Santa Fe: http://www.chowhound.com/topics/519004
I ended up changing my hotel to be near Chapultepec, but I did have to work in Santa Fe for a few days. And while there were a few mediocre meals, I did have one very good meal at Los Canarios in Santa Fe.
Five of us ate there for lunch and every one of our meals was very good. Perhaps my favorite of everything though were the appetizers: pescado al pastor tacos. I'm not sure the kind of fish (forgot to ask), but it was cubed white fish, marinated and cooked ala al pastor (though likely not on a spit). It was amazing. Hand made tortillas (both yellow and blue corn), marinated and slightly charred fish that was deeply flavored, but still tender, all adorned with pickled onions, cilantro and guacamole. Appetizer, but best part of the meal for me.
I had the snapper (veracruz style), which was wonderful, and, though I can't remember all of what my colleagues had (all locals btw), they were equally satisfied.
It wasn't cheap... the bill for five of us ran around 1,600 pesos. But given that the service, food and ambiance are on par with some of the nicer places in the city, it was very reasonable.
So, if you are stuck in Santa Fe and can't make it to Polanco or other areas in the D.F., don't fret. There IS pretty good food around.