Just to insert: This is NOT a zero sum game.
Think of it as a Bell Curve: You'll always have some who will "pirate" regardless of price, and some who will always purchase, regardless of price.
But, if you price your product right, you can capture a large portion of your potential readers as paying customers.
In other words, if you charge $10000 for an electronic copy of the Harry Potter collection, you'll likely end up with very few paying customers. If you charge $0.01 for the same, you'll likely end up with very few "pirates." So, the main goal should be, to find the price point where your profits are maximized. It's really as simple as that!
DRM is much, much less important than price, because while it may deter some from "pirating," it will also deter some from buying.
So, the moral is: IT'S THE PRICE, STUPID!!! (and the desirability of the product, of course
