I say forget med-surg. I went straight into OB (almost) and have never regretted it for a second (I've been doing it about 5 years now). You get med-surg experience while you are a student and after you go into OB, because pregnant women get sick too. Plus, if you think about it, nurses who have been in OB for years are not up to date in med-surg and they manage just fine. I firmly believe med-surg is a specialty in its own right and there is no such thing as a generalist background in nursing.
Med surg in the facility I worked in, was basically a place where they ate new grads and spit em out. I did not need to have my confidence shattered or face a lawsuit caused by unsafe staffing conditions in med-surg! Of course, this is not the case in many hospitals and a year in med-surg may be best for you. I think it's a very individual decision. If you do med-surg, I would go into a gyn unit.
If you do want to go straight into OB I STRONGLY suggest you take some extra courses in that while in nursing school
. There are several universities which offer theory courses by distance. Just get an OB nursing journal and you'll see ads for some. I did that and also took my neonatal rescusitation (NRP) and a fetal heart monitoring course before grad and did all my consolidated practicums in OB. You can also look into taking extra seminars or classes about neonatal nursing.