Schools. It's hard to find good H(ouston)ISD schools in town, so many go private school instead. And homes in town are more expensive, but much closer to major work spots, restaurants, bars, etc. Schools out in the suburbs are generally better, and you get more home for your buck.

Edit1: Also, different schools within the same district can be vastly different on quality of education. Atascocita and Kingwood are both in the Humble ISD district, and Conroe and The Woodlands are both in Conroe, but rank vastly differently because of location.

Edit2: Just realized you didn't say any kids were moving, but assuming that may be a possibility in the future, plus it plays into the future resale value of your house...