The school's insurance program used to be awful, but we just changed to Aetna this year, and it looks pretty good. I don't remember most of the details off-hand, but I believe that there's a 90/10% split, and a prescription plan. No vision or dental, unfortunately. I'll post more info when we get the information. (Or when I find it in the bottomless pit that is my bag... we may already have it.) They say that they are not an HMO, but they do have a preferred physician list.
If you join SOMA (Student Osteopathic Medical Association), you can also buy insurance through them, which is what I did for my first two years. It has an 80/20% split, and a prescription plan (a $10-20 co-pay). It used to have vision and dental, but that's been changed for this coming year. (One of the reasons that I probably won't go back to them.) Some people have had problems with billing, and they only cover lab charges up to a certain amount. (Not too high, because one of my friends is getting screwed by it.) However, you can see any doctor you want without having to worry about referrals, which is kind of nice. I'm still probably going to switch to the school's plan even though it's a bit more expensive... you get a lot more for your money.
Paige