I know that out of towners generally ask this topic every 2-3 days, but please keep in mind that I have lived in Texas for more than 15 years (and I was born here as well).
I am looking for Tex-Mex, NOT Mexican or a Taco Stand.
Please not counter service and somewhere that I can at least get a beer.
It could be anywhere from traditional (Matt's El Rancho) to something more eclectic.
My wife and I are moving to Austin the last week in March and I am already anticipating the food especially the barbeque (Central Texas is the best in the world).