A simple but reliable Thai place in Rice Village, not far from the excellent Ginger Man pub. The pad Thai noodles were particularly good, and in general the classic dishes worked well: try the papaya salad or the vast tom yum goong soup that anywhere else would be a serving for four but, hey, this is Texas.
There is also a branch nearby: 5211 Kelvin Drive, Dunstan, (713 524-0283) that is apparently highly consistent, not surprising as they seemlngly share a common kitchen.
Susan
Houston has excellent restaurants representing a wide variety of cultures. Unfortunately, I agree with the 2/10 rating for Nit Noi, but if you're looking for Thai food, my two favorites are Asia Market and Thai Restaurant (actually a small Asian grocery store with 10 small tables and food service--the green curry with Japanese eggplant, boat noodles, curry puffs, and friend chicken wings are among my favorites) and Vieng Thai (which is BYOB), where the Basil chicken and papaya salad are quite good.