I'm an RPCV Morocco '08-'10. As I'm sure you are now aware, the application bureaucracy can be a nightmare. I applied in Sept 2007 and left for pre-staging in Sept 2008, which is a pretty standard wait time. My suggestion is patience, patience, patience. And, as annoying as all that bureaucracy can be, it's 10x worse once you get into your host country and start doing projects, grants, etc.
I'm glad I served because as an undergrad I was determined to do grad work in development. After two years in the field, I am 100% sure I couldn't do it long-term. While Peace Corps can be incredibly rewarding, there are also daily reminders of how development work can actually be debilitating to a countrywhen applied improperly. However, my specific sector (Youth Development) reignited my REAL interest in working in the classroom, so that's what I'm applying to now.
As for grad/career, I only applied to one Peace Corps Fellows program, so that benefit wasn't a huge one for me. Several of my friends have taken/passed the Foreign Service Test and the non-competitive eligibility can help if you are interested in a government job. USAID recruits like crazy from RPCVs. Like the previous poster said, I think the best benefit comes from the ability to talk about my experiences in my SOP, interviews, etc. A line that one friend jokingly used once in an interview was, "If I can do all of that in Arabic and Berber, think of what I can do in my native tongue!" I know that my experiences in a Moroccan classroom feature heavily in my own grad school applications.
Hope this helps.