If you're coming to San Antonio, then it is required by law that you eat at one of the many excellent Mexican ("Tex-Mex") restaurants, and ironically, most of them are located away from the Riverwalk.  Some of the favorites are El Mirador , Rosarios , Blanco Cafe , Picante Grill , and El Mirasol .  Any one of these places will give you great Tex-Mex food like enchiladas, beef tacos, chalupas (tostadas), beans, rice, tortillas, chips, salsa, etc.  Of this group, El Mirasol does the best authentic Mexican food with dishes like "pork stew" and veggies or enchiladas with mole, chipotle and other savory sauces.  If you're on a budget or in a hurry, then you really can't beat the quality of food for the value at any of the Taco Cabanas throughout town.  Whether it's breakfast tacos like chorizo & egg or carne guisada plates, or the "super tex-mex" plate, Taco Cabana consistently serves up good food at low prices.  You can eat a huge Tex-Mex meal there for under $5, and the breakfast tacos are only one dollar each.   If you are looking for something other than Tex-Mex, then there's plenty of other options.  For a unique experience in a legendary "leaning" building, try the Liberty Bar , where you can get some of the best pot roast you've ever had.  Want to experience the Texas Hill Country without driving too far?  The Scenic Loop Cafe is the place to be for wonderful steak and seafood dishes while dining out under the stars listening to local musicians play on certain nights.  Looking for the perfect, romantic place and money is no object?  try Silo or the Grey Moss Inn .  Also in this same category are some very good, high dollar restaurants on the Riverwalk:  Citrus , Las Canarias at La Mansion , Pesca at the Watermark , and a less expensive place on the Riverwalk with the best guacamole in town is Boudros , which offers a southwestern flair on steaks and seafood.  Try the fish enchiladas!  Yum!   Speaking of seafood, some the best fried catfish at reasonable prices in a relaxed setting is the Clear Springs Restaurant.    A hole in the wall place with some of the best Indian food is at India Oven .  The chicken makhani is the best! 

For something really different, try Drink opposite the Hotel Contessa - this is a classy wine bar that serves great tapas and has live music on weekends. They focus on affordable wines from all over the world and the staff is extremely knowledgeable.

Have fun!