medical22, I hope I'm not lumped in the "acting childish" category. I mean no offense to you, of course, but I stand by my original reasoning. There are at least several others here who feel the same way about plagiarism, so it's not entirely unfounded.
Why don't you check out the sites Popoy and I listed, and follow the suggestions of others to search for more PS's. Personally, I think that there is no single correct way to write a PS; either format you mentioned I think would work. Me, I started by telling a story of a pretty cool athletic achievement (took about 1/4 of the PS), then segued into talking about my work ethic by arguing that both athletics and scholastic achievement take the same qualities (perseverance, etc.). I then talked about the selection of my major and worked into describing a leadership role that I thought was significant, then described one of my volunteer experiences, then used that as a springboard into a paragraph about why I want to practice medicine. My conclusion came back to the athletic thing to tie it together. I feel like a real jerk for not fixing you up with my essays, but I hope that I've helped you at least a little bit.