We don't have an inexpensive hobby. But you know thatt. Even though our passion for excellence can often leave our bank balances a little light, you don't necessarily have to take out a second mortgage just to dip your toes in the waters of AV enthusiasm or even give your existing system an upgrade. Whether you're just getting started and looking to build a good AV system on the cheap or you're an old married audio/videophile looking to get your regular kicks with a spouse-mandated AV allowance, there are oodles of great discs, downloads, devices, and doodads to be had for less than a hundred bucks. Here are a few of your choices . . .