get the hard stuff out of the way first, do not take surgery and ob/gyn back to back - rest is up to you
my sched which I have been very happy with:
peds, ob/gyn, im, surg, geri, rads, psych, family
the surgery shelf is largely im based (at least for DO students) so taking im first was definitely a big help.
I remember a lot of people were really anxious about picking the "right" 3rd year sched, and now that I'm in it, I can see it really doesn't matter.
-J