Noise Canceling Headphones

After having watched an infomercial about noise canceling headphones, I had to look into them. They contain circuitry designed to offset and cancel out background noise; those who have them tend to love them, especially on buses, on subways, on planes, near noisy PC fans, or in sociology classes.

The cream of the crop is Bose, but they are pretty pricey. At the other extreme, Panasonic makes a very inexpensive set, but it doesn't get great reviews. My own preference is for the Sennheiser headphones.