I think the best DRM would be DRM that BENEFITS the buyer rather than punishing the pirate. Instead of punishing someone for playing a non-legit copy of the game, provide tangible incentives for playing a registered copy. Some games already have a system that works like this related to their multiplayer aspect. You can play the single player game as much as you want without interference. No DRM to worry about for the basic game, no punishment for installing multiple copies on your home computers. But if you want to download additional content or join the multiplayer community, you must make an account and register each copy separately. Since the licensing information would be hosted on a secure server separate from your home computer or the individual game disc, the game developer would have additional control over registration and it would simplify DRM management while facilitating digital distribution of the game and allowing the gamer to decide how and where he would like to play the game. The developer could limit the number of re-installs or registrations, but from a customer service standpoint, they would be wise to provide more if asked. Basically, very similar to how Steam works, but applied to individual games supplied by a game company, either on-line or in the store.
I would also accept one of those spinning matching wheel thingies old lucas arts games use to come with for copy protection. Those things were so fun!