Geographically and economically, it's a great place for companies of all sizes.
And for the record, I agree there are more oil/gas companies in Houston. Many of the operators on the Barnett play are based in Houston.
Here’s the list of CITIES with the most Fortune 500 companies headquartered there. New York City leads the list by far followed by Houston.
http://money.cnn.com/magazines/fortune/fortune500/cities/