It doesn't really matter to be honest... but what does matter is you HONOR medicine and surgery... no questions asked. I've been on interviews where the interviewers specifically have these forms in front of them about your app asking "honored medicine : yes/no," "honored surgery: yes/no." so these two rotations are REALLY critical. I've even heard from one faculty person that they even like seeing honors in OB/GYN cuz it shows you're well-rounded and do well in all arenas. So the bottom line, work your butt off in rotations and it will definitely come out in your app with your dean's letter, etc. It also goes without mention that you honor your ortho electives/sub-Is.
Not sure how your school is set up, but if you can take at least one elective (obviously non-ortho) before starting your core rotations I think that often helps getting your feet wet before it really matters, and just understanding how things work on the wards... with rounds, notes, orders, discharges, consults, checking labs, etc.
Finally... I took a long FM rotation the fall of my 4th year and was ready to poke my eyes out, but took Step2 CS immediately after and thought it was a breeze... that exam is not difficult regardless, but just a thought.