Tmazz had his tongue in his cheek when he says not to get him something "too good," but he has a point. Getting him something fantastic like the Usher or Spica may be the wrong way to go. Really fine speakers will show off all of the flaws in the Onkyo, which will be counter productive (and and may give him the bug inadvertently). I'd keep it simple for him and run with the stuff made for the wider market, like the Bostons, late '90's Polk (not earlier, yecch),or Paradigm.
Keep it simple and he'll have the best results.