In Taos, my favorite New Mexican restaurant is Orlando's. Spectacular chile whether you choose green (my favorite), red or caribe. Try "building your own bowl" with posole, chile, and other ingredients that you choose from the menu. His carne adobada is also fantastic.
There's a small place on the corner just south of the plaza on the Paseo del Pueblo called Rellenos Cafe by Antonio. Dynamite! Antonio also has a more upscale restaurant in Ranchos called "Antonio's", go figure, which is always consistently excellent and creative.
I also like the burritos from Rita's northside which is basically a trailer with a counter inside and seating outside.
Roberto's on Carson Road is kind of a surrealistic experience if they are open. Roberto seems to take MANY vacations! Very limited traditional Mexican menu but excellent execution. Make a reservation. Nice place, not a hole in the wall.
For a truly memorable dinner that's not Mexican and much more expensive, go to Joseph's Table. Be warned, though, we've found that Joseph's can be uneven. With his new location, we've had one really mediocre meal but two that were stellar.