Hit the river walk for lots of GREAT food and drinks!!! Ahh, i can remember the great 32 oz Margarita at the little mexican food place right next to one of the bridges...sorry i can't remember the name of the place...after having one of those(or two) you will hardly remember your name let alone the name of anything else around. There was a great nightclub right on the river just down and across the river from the margarita place that has 3 floors and different music on each one, so you can get a little of everything ( i think it used to be called polyesters)...hit this after you have one of the margaritas and you will dance like a madman. i have stayed at a few places there, none by the airport though...when i go i like to stay where everything happens(read that as, after i get toasted on the riverwalk i need to be able to stumble back to my room). There is the Marriott Riverwalk (something like $120 a night) great place, the Riverwalk Hyatt nice as well, and numerous other places.
Seaworld is OK, i have never really been into that kind of thing unless i have my daughter with me.
Never been to Fiesta Texas...New Braunfels is nice, and the tubing is pretty relaxing. I must agree that Schlitterbaun is not the best place in the world if you really want to go on the rides...like has already been said, you WILL stand in line for 45+ minutes for every ride.
For a more romantic dinner(also read a little more pricy, but still reasonable) try the Tower of the Americas. You cannot miss it in the downtown skyline, it is the tallest thing there, and almost looks like the tower in Seattle. Less than a 5 minute walk from the riverwalk area. Very good food, and you can't beat the revolving restaurant at sunset.
Try to make it to the farmers market(or whatever it is called) if you can. Good deals on lots of things, lots of them authentic mexican items. If limited in time however, this can wait for another time.
Man i really want to go back soon...I love it there, i would make monthly trips there when i lived in TX. Lots of fun, and many things to do.
Oh yeah, a couple more things if you are into it...There is an animal park just north of SAT up I-35 (again, don't know the name) like one of those open areas with animals from around the world...just imagine zebras and buffalo and various other animals sticking their dirty heads in your car type place. Right next door to that is a natural caverns place that you can walk through caves on guided tours and stuff...i think that place is called natural bridge caverns. Fun, but again maybe more things to do with the kids instead of a girlfriend on your 21st birthday.
