It sounds like the Standard IOS developer program should work for you.
You're right in assuming that the University program wouldn't be for you. It is really meant for schools teaching IOS development.
The Enterprise program sounds like over kill for what you are looking to do.
In the standard program you can do what they call Ad Hoc distribution. You can distribute to 100 iOS devices directly, not through the App Store. Do you think you'll be distributing to that many devices?