Amazon.com's DRM for downloads suggests where we are headed:

"The goods you buy from them don't belong to you, they can take them away from you at any time, or change the deal you get from them without any appeal by you."

I'm guessing it is along the lines of, the DRM software calls home often, snoops around your hard-drive for upapproved software and patches, if it does not like what it sees, it disables your access to the content you rented from them.

Yeah, this will challenge the rogue servers out there. I hate to tell you guys but your content is not worth nearly as much as you think it is. People want 99 cent downloads free of restrictions. Let people buy 'keys' that are linked to "buys" and the file sharing problem goes away. Try to charge 10$ for a crappy film, there is too much incentive to bypass retail opportunities.

A dollar per viewing seems fair. Make the DRM limit the views, not the movement to other devices. If I want to see the film 5 years from now I'd gladly pay another dollar.