I've found that people have widely varying opinions about Mexican food, so what one person likes, another may not. The little places that have popped up all over town, La Tapatia, are a very good value with copious proportions, even with meat. Chuy's is excellent, with a nicer environment than La Tapatia but more expensive. Best view/best place for a group: Iguana Grill in Lakeway (overlooking Lake Travis). There are a number of nicer places: La Fonda San Miguel, Manuel's, Iron Cactus, but you are paying for service and ambiance as much as the food. There are also single neighborhoods Mexican restaurants all over town, as well as a lot of restaurants that serve TexMex dishes. I think you can go for years without going to any place twice!