5. Sanders/Wingo Advertising Inc.

Sanders Wingo Advertising Inc. is the largest full-service advertising agency in Texas. The company provides branding, account planning, public relations, strategic planning, media planning/buying and creative services.

Clients include AT&T, U.S. Postal Service, State Farm, American Heart Association, Shell Oil, and Blockbuster.

In 2008, the agency’s billings were in excess of $111.7 million–up 24% from last year.