It depends on why I like the hospitals I do. If I was wanting a natural birth and one hospital was very helpful in that area while the other rather tie you down to the bed, then the hospital would be much more important to me. If both hospitals will respect my birth plan but maybe one is just newer than the other or something else little, then I would think the OB is more important. What are your reasons for wanting certain hospitals?
ETA: In regards to what PPs are saying, the OB does so much more than "catch the baby." At least in my experience, my OB was awesome and there for most of my labor while I was at the hospital. He was constantly checking on me and talking to me and just hanging out and BSing with my DH. It was really nice. Plus, I was 99.9% sure he would deliver my baby. I specifically asked him what the chances were and he said the only time he misses a delivery is if it his wedding anniversary--which happened to be a totally different time of year than my EDD. So again, depending on the OB, you don't always have to think along the lines that you will more than likely get who is on call.