lapollerita, do you want something like carne fajitas? Those I make myself at home. The best mexican food are the ones you make at home and I have discovered that I can but I have friends in Mexico that I call should I need a recipe or something.
As a mexicam-american, I must say that Maria Felix sux, Cielito Lindo in Palermo is pretty good, love Taco Box (several locations)and D.F: in Puerto Madero is awesome. Heard la fabroca de tacos was amazing and super auténtica, need to try that one for sure!
For cooking at home, china town has the goods, real tortillas (no rapiditas), jalepeños, cilantro, salsas, chips, etc