I applied to dental school and ended up deferring the acceptance I recieved in late May from a school at which I had been wait listed. I had a research job lined up for this year that I had to call in a big favor to get so I really didn't want to back out. Also, I had already submitted my next round (this year's) application. Further, I was out of the country when I got the phone call. They wanted a decision within 24 hours but with all the time conversion I pretty much only had 6 hours to think on it before deciding and I had a lot of factors to think about. I asked if I could take a deferment and they let me. I guess I was pretty lucky. If I hadn't gotten the deferment, I would have accepted and be in dental school now, not a bad alternative. I have gone back and forth over this decision since the moment I made it, but I am glad I decided to wait and reapply.
I don't know if that really applies to your situation. However, if you wanted a true deferment story there it is.