Master's degree in Communications, Marketing, or MBA?

I am trying to decide on a Master's degree program in either Marketing, Communications or an MBA with focus in Marketing or Communications. My undergraduate degree was in theatre, but after years of working in film & TV and then transitioning into media relations/public relations as a Field Producer, I now work for a production company that specializes in Corporate Communications projects. They create a wide variety of business media (sales videos, trade show media, interactive media, video reports, and even custom games and other software). I want to increase my knowledge of Mar Comm so I can better understand our clients' needs and brand strategies and be a greater et to my employers. I also would like to earn a degree that will incorporate my varied production experience if I ever decide to transition to the client or agency side. Our clients are usually Directors/VPs of Marketing Departments or their direct reports.