San Antonio - Riverwalk
[my edit after original post...typos remain--you can easily google these venues]
If you prefer to spend your per diem at the local level, I'd suggest Bohanan's, Le Rêve or Little Rhein Steak House. Bohanan's isn't a "river" restaurant (it sits across the beautiful Majestic Theater), but the food is very good. Service had been spotty (last dined 06/05 since I live in Japan, now) over 10+ trips, but the food trumped. Great room.
Little Rhein Steak House is "river"...and an SA tradition for date night. Follow the adage of '...don't order seafood at a steakhouse....'
Le Rêve [I'm a red-meat diner...I prefer to eat what I know, and I spend my money on prime aged beef, for the most part] is an adventure. If you can get a rez, you shouldn't be disappointed. If you are comfortable with continental cuisine (read: perfect portions accompanied with perfect sauces (and I mean perfect sauces), then try for Le Rêve's small dining room on the "river."
You'll never roll the dice on either of these local establishments--great food, great pride in presentation.
For a perfect end to your evening, I would highly recommend the Havana Riverwalk Inn's Club Cohiba. It is located on a very quiet bend on the river. The bar is in the hotel's 'dungeon' but just a small set of stairs away is a broad veranda that offers one of SA's best kept secrets--quiet, romantic river vista.
I'm stuck here in Japan with the best sashimi and sushi, and all I can dream about it a fine USDA Prime dry-aged steak. Go figure. In five months, after my retirement, I'm sure I'll be in the land of Prime aged, dreaming about sashimi! Who's ever happy?
What typ eof food are you looking for?
Personal favorites of mine are
Biga on the Banks for the upper scale affair.
Pieca D'Italia for moderate Italian.
Jim Cullum's Landing for great music and drinks.
Boudro's, Zuni Grill are great eclectic places
and Rio-Rio or Original Mexican Restaurant offer great portions and a taste of that Tex-Mex flavor.
You can always peep this site to see a few more options.
Sorry to plug it, but that's what it's there for.
)Safe travels, enjoy your stay in S.A.