I own over nearly 100 games on Steam, mostly bought on sales. Despite the tons of titles I bought, I miss the experience of actually owning a copy of the game, along with the box and manuals that came with it. More importantly though, I think it's scary that Valve can one day decide to totally ban a user from their purchased game because they didn't like the behavior or actions of an account holder (e.g. cheating in a Valve game or account getting hacked).