2 nights in Houston!!
If you feel like driving around - here are some suggestions.
The Telephone Thai - (real name Kanomwon) on Telephone Road. Very good Thai (28 rated in Zagat) - looks like a dump but who cares.
Upscale fusiony Indian - Indikka on Westheimer close to downtown. Nice decor, nice cocktails good Indian cuisine - not typical Indian but good - I love their vegetarion sampler plate.
Cheap Indian/Pakistani - Sabri Nihari on Hillcroft close to Highway 59. They do an amazingly good brunch for about $10. Good variety of dishes, Nan bread served about 10 seconds after it is made. Good Nihari (of course) and haleem. Pretty good goat dishes. If you do the buffet I'd avoidthe chinese dishes which they view as an enhancement to the regular fare.
Theirs loads of Vietnames places where you can get a great bowl of Pho. There's also Treebeards (lunchtime only) where you can get cajun buffet style service.
Steer clear of most of the barbecue places - not that good.
Pappas places (mentioned by others) are pretty good (except for the BBQ Pappas).
Welcome to Houston. James is right, the Reliant area is pretty much a wasteland, lots of chains, only a few places of notice. Here's a former thread:
Note the Frenchy's Fried Chicken mentioned in that thread has closed. I will mention the Pappas BBQ on Main near Reliant, another part of the huge Pappas restaurant empire. Not the best bbq in the city by a long shot but since you're from Boston and may be wanting to try some it would be convenient. Most of the best bbq places close by 6 or 7 anyway but Pappas will be open until 10 pm or so. Pappas places are chains but above average for chain fare.
I gather from your post you're really looking for evening fare only. To get the best of the city instead of just fill you stomach, I'd suggest heading up to Montrose (where Feast is) or mid-town, both within a reasonable cab ride.
Uichi, El Real, Underbelly are some of the hottest places in town right now in Montrose; there are others in there so new I don't know anything about them.
Reef and the brand new one from Monica Pope, Sparrow Bar and Cookshop, open only a couple of weeks, are in mid-town.
You'll find lots on some of these here on this board, in the Press or on 29-29.com or just by googling and turning up blogs and discussion boards.
The usual question, car or not? Trolling the Boston board the last couple of days and the Mexican food seems to be lacking somewhat. Close by is a Tex Mex standard Pappasito's for good grilled meats. I haven't been in a few years but I doubt much has changed. Since you eat everthing, we have Feast, a local favorite of many, a snout to tail place. Edit, Reliant is a bit of a culinary wasteland, so Pappasito's is a suggestion Feast is a 20 minute plus cab ride. Others will make suggestions along the light rail.