So I went online in search of a taco seasoning mix--it isn't mine, so I don't feel free to share it, but it had chili powder, paprika, onion powder, salt, garlic powder, cumin oregano, cayenne and black pepper. For proportions, check http://www.diylife.com/2008/04/10/taco-seasoning-from-scratch/
It's for a pound of ground meat, but I used it on a pound and a half, and it was great. Then I added tomatoes, avocado, forgot the onion (oops!), and romaine. Since Elizabeth was eating with us, we took out her portion before adding the cheese and dressing (she's gluten- and dairy-free). Then I added grated cheddar and the dressing.
Dressing was a bit of a problem. I looked at several recipes online that called for picante sauce, of which I'm not particularly fond (bad thing for a Texan to admit, I know). But I found one with a sour cream base, Italian salad dressing (I used Newman's Own Vinaigrette), lemon juice, minced onion (forgot it again), a tiny bit of chili powder and salt and pepper. Find it at http://www.cooks.com/rec/doc/0,1715,152165-25199,00.html. We decided it was delicious and just right.
Served with a platter of fresh, Texas-grown corn on the cob. No dessert needed. Yum!