The Gumroad Blog - How to: Sell Films

If your film isn’t released yet, but you’d like to accept pre-orders, we also make that super simple. Just create the product as you normally would, but make it clear to your buyers that they are pre-ordering the film. For the file attachment, just upload a PDF with info on the film (or, even better, some bonus content). The buyers will be able to download this content immediately after pre-ordering. On release day, just update the file with the final film content, and notify your buyers in one click right from Gumroad. Their original, secure download links will automatically update to serve the film, and we’ll even auto-insert their unique link into the notification email.

 Possibly the easiest store front site I've come across. 

What about you? What's your e-commerce site of choice and why?