Spicy Pork Chorizo, some Oaxaca cheese, beans if you want them, add whatever else, Guacamole, et cetera. I do that if I don't make some generic ass Taco Bell'esque tacos.
I prefer to just make Carne Asada Street Tacos when I'm not feeling lazy, since I basically just do some Steak or Chicken with Tajin and a charred whole Jalapeño. Topped with some Pico and Cilantro, and a side of Spanish Rice and Beans. Of course, spicy blended green chili with an avocado tossed in to make it creamy.