Reef and Stella Sola are by the same chef/group but are pretty different and both great. Brennans ($$$) is close to downtown, if you want to have some upscale Gulf/creole cooking in a gorgeous setting, go there.
You will be staying very close to a newish development City Centre or something that has a tapas place (Andalucia), House of Blues, Guadalajara, Yao. If I had to go to any of those I would go to III Forks (steakhouse) but I have only been to the one in Dallas, but it would probably be the best option there. Otherwise have the hotel drive you somewhere or take a cab. The Grove is in Discovery Green which is next to the hotel, the food there is not that great but if you want to walk there and have a delicious chili margarita and sit outside and see the view, that is worth it.
If you are around downtown and want something local and casual for lunch have someone point you to Hubcap for burger and Treebeards for cajun (red beans/rice, etoufee, etc)
Yao Restaurant and Bar
9755 Westheimer Rd, Houston, TX 77042
1001 Studewood, Houston, TX 77008
We spent Easter weekend in Houston (we live in Toronto) and enjoyed:
Feast: 219 Westheimer
MockingBird Bistro: 1985 Welch
Au Petit Paris: 2048 Colquitt
Mockingbird & Au Petit Paris are both very good but not special. You will find similar restaurants elsewhere. Feast was very special and for the more adventurous eater. I had the veal sweatbreads as a main.
You can actually take a cab. We stayed at Lovett Inn (Westheimer & Montrose) and took a cab to Mockingbird. Be prepared to know how to get to your destination. None of the cabbies knew how to get us there. Cab fares for our destinations were cheap, under 15$ 1 way.
Hmmm. Is there only one here? I'm finding 2 - near the airport and downtown. Presume you'll be staying downtown? Will you have a car? Houston is very spread out; there is public transportation but a car or cab are the best ways to go and cab rides can get expensive, so we can limit recommendations appropriately.