What's So Great About HBCU's Anyway?

This is my question. I hear all kind of people lauding the HBCU experience and seem utterly enraptured with the idea that they will be able to spend the four years of their undergraduate experience with people who share their same ethnic background. 1st question: Is this at all representative of real life? From my personal experience I have found that we, or at least in the upwardly socio-economic realm that you high achieving and socially conscious African-American (predominantly) hope to take part in, live in a white world. How will an HBCU where you will be surrounded by people like you and taught be professors like you be at all representative of real life? Or at least the one you hope to be living? My 2nd question involves personal and academic preference. I have been accepted into a number of Universities and can go anywhere I want. So what would make me want to attend a HBCU rather than a more traditional Ivy League school or one of its equivalents when my goals is to become as educated as possible and subsequently be the most qualified for any future position or work that I would like to pursue. Furthermore, how diverse can an HBCU be and how much can you learn about other cultures/environments when you are surrounded my only one megaculture?