My suggestion would be HSU Research HB1-MK2 bookshelf speakers. They are just a bit higher than your budget at $169 each. I did alot of research recently on bookshelfs and decided on these. If you want to read up on them a bit, there are good reviews on hometheaterreview.com and steromojo.com. Anxiously awaiting a review of these on Audioholics(they reveiwed the older version of these quite a few years ago).
If your son will not be using a subwoofer, you might find these make a decent full range speaker for a bookshelf due to the 6.5" woofer.