Speakers

Unlike oxygen, food, or water, surround sound isn't necessary for survival. But if you recently upgraded to a slim, big-screen HDTV, you're probably feeling a need to update the audio part of your system with something equally tasty. Home theater used to mean huge tower speakers or chunky satellites paired with subwoofers that took up as many cubic feet as an SUV's gas tank.

Call it the invasion of the on-walls. Or just call it a change in the way speaker companies think about design. Either way, the audio world is being overrun these days with speakers made to go with flat-panel TVs. What these systems have in common are shallow, wall-hugging cabinets.

Most people would agree that the real goal of any audio system is an illusion of transport - the musicians to the listening room, the listener to the recording space, or both to another place entirely. I'll tell you right now that NHT's long-awaited Xd speaker system, though not without its flaws, is one of those rare products that lives up to this promise.