BW Tech & You Columnist Steve Wildstrom screens some Apple TV. Like nearly all products coming out of Apple these days, Apple TV is brilliantly executed. It's a set-top box that lets you play content--movies, TV shows, podcasts, photos, music--from an iTunes library on a computer in your home on your television set. The problem is that you can only play iTunes content--and that leaves out an awful lot you might want to see