I've got kids near that age. They absolutely love my Onix SP-3.It's a very well built, cool looking tubed integrated putting out 38 very punchy and fun watts per channel. You don't get a remote so that might be a deal killer but you can buy a new one for $600. If space is a problem, Paradigm Atoms would be nice and if space is not a constraint, you can find used ADS or something of that caliber for cheap. My kids come right out of the computer to their preamps and on to NHT MOO powered monitors. They love what they have but both would prefer to have an Onix and Zu speakers but Daddy's pockets aren't that deep.
Another important consideration is what he'll be listening to, and whether or not you want to hear it. My boys use headphones much of the time and I am always glad when they do.
Another important consideration is what he'll be listening to, and whether or not you want to hear it. My boys use headphones much of the time and I am always glad when they do.