From someone who actually goes to Harvard...There is no magic recipe to get in. I know the Dean of Admissions very well, and she reads the entire application, looking for something that makes you unique. This goes for the Med School as well. I had a moderate GPA, average DAT scores, but had lots of "life experience". Personality, People skills, self-drive, etc. etc. I expected my classmates (Med and Dental) to be nerdy, rich, stuck-up, super smart, top of there class etc. You are much more likely to find very-touchy feely, "went to Africa to start an AIDS clinic" types. People that have done a lot for other people, and didn't do things just because they look good on applications.
If you take a year off and do something unique you have a very good chance of getting in. Once you are here it is very laid back. Pass-Fail, very supportive faculty etc.
I love it here, but I don't know if I would delay school a year just to get in here, that is an awfully big gamble.
HSDM class of 2011