My crystal ball is in the shop for a tune-up. However....
Just helped a 1st time buyer purchase in Pine Mill Ranch in Katy. That entire Katy (including Kelliwood) area is doing very well with the Energy Corridor growing, great Katy schools and easier access into Houston via I-10 and Westpark Toll Road.
Tomball is also growing very fast, but for different reasons. Mainly mature trees, small town feel and more land for the money plus great Tomball schools. Hwy 249, once widened, will improve odds of appreciation. Strong employers like HP and United Airlines.
Kingwood and the NE areas of Houston have a lot of growth potential. Great communities like Kingwood, Eagle Springs and Fall Creek. Wonderful Humble schools and quicker access to downtown Houston than any other out-lying area. 25 minutes from Eagle Springs at 7am rush hour.
All that said, the location of the home, condition of the home and the general local economy will have the biggest influence on your home's future value when you sell in 5-7 years. If you think we are at the bottom with the economy and the future will grow in 5-7 years, you will be fine regardless of where you purchase. There are many other factors (floorplan of home, quality of builder, things YOU do to the home after purchase, etc) that effect the future value. Your best bet is to get with a Realtor to discuss what you want to purchase and why, then all of these factors can be accessed.
I work all of these area and show buyers here. Let me know if I can assist you. Good luck!