As you said, perhaps you should look at what they charge for a waterbirth at the hospital. And then figure out what your deductible and co-pay end up at. And then think about the fact that, with a hospital provider, at best you have 20 minutes with them in a prenatal. More common is 5-10 minutes, tops. WIth a homebirth midwife, you will get an average of 45 minutes to a full hour with your midwife. Midwives spend more time in counseling on nutrition and exercise (two main ways to avoid a cesarean), as well as educating you in general as to what is going on in your body and getting to know you fairly well...because, after all, your birth will be the once in a lifetime chance to experience that moment, and midwives want to be a familliar friend in the room, not the stranger who waltzes in to catch!
Think about procedures you'll come against in the hospital...eye goop, routine suctioning, worrying about when the cord is cut, wondering if they'll offer you pain relief the first time you say you're uncomfortable or the second you hit transition...instead of physical and emotional support...
I don't think it'd be a problem at all to make a 45 minute drive to the hospital, if a hospital philosophy is what you hold when you think about birth. BUT if you are considering a homebirth, please don't let insurance be your ONLY consideration!
I have a client (and friend) who drove an hour and a half to birth her VBAC at a birth center. They are very, very far from a hospital at home and they wanted to know that, in case of transport, they had somewhere within fifteen minutes to go. The birth center put them 5 minutes away, door to door. So, she drove an hour and a half to be with midwives she trusted to encourage her to birth the way she felt safe doing! She called and told me when she made the choice that she had had the FIRST good night's sleep in MONTHS...and then she tore up her birth plan and had to rewrite it. She was able to say what she WANTED, not forced to defend herself against what she didn't want.
Just a thought.