Restaurants in The Woodlands
Right at the the Woodland's Mall there are several restaurants - I can recommend 3 of them - Brio's for italian, Cheesecake factory for American or PF Changs for Chinese. I have heard that there is a Black Walnut Cafe up there as well, but have only been to the one down on Kirby - this is a fabulous restaurant with amazing foods and desserts! Grotto's is also great, but again I have only eaten at the one near the Galleria.
Other ideas: Pappadeaux's or Landry's for cajun seafood, and Saltgrass (ribeye) for great steak.
hankster, I assume you're coming from Dallas via other posts. Though The Woodlands is a bit of wasteland for ethnic food due to the dominance of chains (as seen by kr36's recs below), regional chains like Lupe Tortilla and Los Cucos (both have locations in Spring, close to The Woodlands) provide pretty decent Tex Mex (since we don't have these places in Dallas).
I hope Houston 'hound start to chime in. But I certainly didn't want to leave your options at average chains that are abundant in DFW.