I woud certainly encourage everyone to get at least an AA and preferably a BA/BS if at all possible. As for graduate degrees, it really does become dependent on the degree. Obviously MBAs and MPAs are great, but most MAs and MSs exist merely to pad resumes and don't open any new doors.
Since I'm not going to be able to get certified as a teacher, the M.Ed. I'm about to complete is going to be used to pad my resume (look, I have a Master's!!). In the future, when I have more education benefits accrued, I would like to earn an MA in history, but that is largely a pride factor. If I ever get the Ph.D., it will allow me to become a professor (which would be a lot of fun), and it will give me the prized "title" that Dano alluded to. The only door it might open for me is that I will receive the knowledge and research skills that might allow me to publish a few books, which is a neat prospect.