If you've graduated from "Guitar Hero" to playing an actual guitar, but you're feeling a little shy about cranking things up, the Waves iGTR ($60) let's you play over your headphones while maintaining the sonic character of playing through an amplifier.
The iGTR is about the size of a small paperback book, weighing 3 ounces and measuring 2.75 inches wide, 4.25 inches long, and a half-inch thick. A compartment on the back accepts four AAA batteries (included), and there's an optional AC adapter input on the bottom. A detachable clip is included in the box, which snaps on to the back of the iGTR and lets you walk around your house like a rock star.
All the interesting controls are located on the face of the iGTR, including three oversized knobs for amp gain, ambience effects (delay, reverb chorus), and modulation effects (tremelo, wah, and phaser). Each knob includes a three-way switch to designate what the knob controls. The control layout is intuitive and easy to manipulate, although some guitarists will balk at the limited settings.