Oh, and gadad: you're right. I guess I thought I'd included that...(esp. in the interview portion)...the way I see it, your essay equals you...so does the interview. They're really very wonderful people, admissions officers are...they want to make sure you will fit at their school, and that is one of the main reasons for rejection in many cases. Harvard, like any other school, has its own culture; without sounding arrogant at all (I hope), there really are people who will not--and do not--fit there. It has nothing to do with their intellectual levels or academic "caliber"; they simply don't fit. I know many people who chose Harvard solely for the name, and usually they end up unhappy. Be genuine, as gadad said, and that way you'll know that it was the culture, not you, if, God forbid, you don't get an acceptance letter.
Thanks for all your comments, everyone! Very informative, and I hope I'm answering everyone's questions...???