Fish tacos in Mexico = the best
If you go to Tijuana, there's a little hole-in-the-wall restaurant called Chuy's that makes amazing fish tacos. I have no idea what kind of fish they use, but the tacos are delicious. If you go to Cabo, there are guys selling fish tacos from push carts, and those are excellent as well.... probably a fresher fish than they use in Tijuana.
If you make your own fish tacos, try using small corn tortillas, but not the crispy kind. Heat the tortilla in a pan until it's soft and flexible, then put your ingredients on it before it cools off, wrap it around the filling, and enjoy.