I thought about surgical specialties in my preclinical years, but now that I'm in my third week of gen surg, I've come to really love it. Plastics is also pretty cool. Gen surg has been getting quite competitive, as demonstrated by this past match, and programs have been forced to choose between highly qualified applicants. Pieces of advice I've gotten along the way have been to get good board scores (duh), definitely take the USMLE if considering allo programs, and doing a sub-I early in 4th year to get a LOR in time for interview season. And they like most, if not all, of your LORs to come from surgeons. Writing a case report or making any other effort to get published will also distinguish yourself. My attending (MD) tells me he doesn't believe that being a D.O. has inherent disadvantages, especially if you take the initiative to be comparable to MD students (i.e. take their exams). But, that's just his opinion.
Why I'm still not convinced this is the specialty for me revolves around the nebulous perception of "lifestyle". My fiance is a MS3 too, so I have a whole other list of priorities to consider. If I were single, who knows, I'd probably go for it.