Ten reasons I can think of to go to graduate school...

• Increase the knowledge base I can apply to software development, in improved software products, and in improved business decisions.
• Improve the quality of advice I give as a software consultant.
• Raise the level of the organization at which I give advice.
• Expand my network of smart, ambitious people.
• Learn principles of economics, finance, network economics.
• Learn techniques for evaluating companies, and the impact of financial decisions.
• Develop mathematical rigor, appropriate to understanding 'AOCP', Knuth.
• Spend time enhancing my skills as a developer and computer scientist, ala SICP
• Sift through all the advice that's been given (Brooks, McConnell, Spolsky, etc) and conduct experiments to determine what are the most useful practices for a given environment.
• Spend time with my ear to the ground on campus for current research and applications in the labs and among the students.