Definitely do medicine before surgery, because you are expected to know medicine stuff but they won't teach it to you on surgery. Also, I found that I usually "pre-rounded" on about 3 times as many patients on surgical services in about half the time; so it helps to be comfortable in the hospital.
I did med first, surgery second and I think I made the right choice. Then I could coast for the rest of the year. In my opinion, you don't learn a whole lot on other rotations that is going to help you on medicine or surgery (except alot of sewing on OB maybe). Since you are coming off of research I would imagine that you are well-rested, so you can take on the big guns up front. If you do surgery last, than you will likely go straight into ortho sub-i's and that has the risk of burning you out early in 4th year (or 8th year as the case may be for you).
I would definitely recommend not doing the ortho component as your first surgery rotation (if they let you take ortho as part of your surgery block) - it would be good to get to know the OR before diving into ortho.
