I realize that this post has gotten off topic, but naturally like every Chowhound, I want to add my bit.
I am very biased. I was born in Texas and have lived for most of my life here with stints in Italy, Greece, Colorado, and California, but I always return home to Texas
My definition of Tex-Mex.......
(which I think of as an American or Texas version of Mexican food.)
IMHO Most NY/NJ Italian food is of the similar vein. Did you see the episode of the Sopranos where the crew went to Italy? Pauley was upset that he didn't get pasta with red sauce (Marinara originally meant related to the sea--mariner. It was a tomato based sauce with seafood.) I know that some restaurants in NY/NJ serve "real" Italian food, but 85% do not. I lived in Italy for two years and most of the wonderful food that I experience had very little to do with what I had eaten at authentic Italian restaurants in the states. So 85% of the restaurants in NY/NJ do not serve Italian food as an Italian would experience it at home. The same is true for "Texan" mexican food, but Texans are smart enough to add their own moniker on it to differentiate it.
1. offer chips and salsa (complimentary with a meal)
2. have combination plates
3. have refried beans made with pork (fat or bacon or similar)
4. serve cheese enchilladas made with true cheese; cheese like products run very far down the list. IMO Velveeta and enchilladas make a terrible combination.
5. serve queso (here is the one exception to where processed cheese is allowable, but I personally prefer queso blanco or another cheese instead) Queso flameado does not count.
6. have the option of crispy tacos (it does not have to be the default option though)
7. serve both flour and corn tortillas (my experiences in Mexico have not made me an expert, merely an experienced beginner; but I rarely saw flour tortillas unless it was for tourists. Corn is subsidized by the Mexican government, they do not subsidize flour. The government recently removed the price controls off corn and there were a few riots.)
8. have Nachos on the menu OR at the very least understand what you are talking about if you ask for them (they should not stare at you blankly)
9. have ground beef as a taco option, but brisket and other beef option are a bonus
10. have a nonmeat or vegetarian option of some sort OR can accomodate the request without resorting to Spanish.
11. have at least one of the following items: Fajitas, Burritos, Chulapas, Guacamole, or Quesadillas.
12. have either mints for free OR sell chicle, peppermint patties, thin mints or have a cookies based upon sugar and any nut. Machines are acceptable, but a counter is preferred.
The next one is very controversial and the last is extremely controversial and people have come to blows over it.
13. have a deep fat fryer in the kitchen. I guess it is possible for a Tex-Mex restaurant to not fry their own chips, but it is NEVER as good, BUT at least an appetizer, an entree or a desert must be fried.
14. accept credit cards UNLESS the restaurant is more than twenty years old and then they are grandfathered.