If your goal is to teach at the university or community college level, a master's and a PhD are necessary. Except in certain fields, like the fine arts, most colleges and universities require their professors to hold PhD degrees. Even at the community college level, most institutions prefer to hire individuals who at least hold a master's degree. Some private high schools prefer master's degrees or PhD as well. So if higher education is your dream job, it's best to invest in advanced degrees.
If research is what you truly love, a PhD is the way to go. Whether you'd like to run a university laboratory, become a respected expert on Shakespearean tragedy or patent a new medical discovery, a PhD will give you the time and space to pursue those dreams. Graduate students receive lab and library access that is less common outside academic programs, as well as funding to pursue research in many cases.
In a graduate program, you will meet dozens of bright, ambitious future colleagues. The connections you make in a master's program or PhD program may translate into references, jobs and other benefits as you progress throughout your career. Your classmates in graduate school move through the same classes with you, attend the same social events and share the same struggles. In addition, the name recognition of MBA from your university may land you interviews in the future.
Even if you choose not to go into research or academic teaching, your graduate degree distinguishes you from the larger pool of job applicants. It shows that you have dedication, persistence, critical thinking ability and creative problem solving skills -- all skills that employers seek in potential employees. Your master's degree or PhD may just give you that competitive edge you need to stand out from dozens or even hundreds of other candidates.