Noise cancelling headphones are really cool, what they do is to monitor the background noise around the user and then sends inversed noise into the headphones thus canceling the noise.  This technique is among other places used on aircraft carriers to protect the ears of the flight crews, and many frequent fliers use them to remove the annoying humming when flying. 

So, the technology is cool, however two problems exist with most noise cancelling headphones;

  1. Price (they are often very expensive)
  2. Power (usually these headphones require an extra battery pack for the noise cancelling part which is bulky and unsexy)

But these Blackbox i10 headphones seem to have something going for them, 1) Not THAT expensive (still the price is not for the faint hearted) and 2) The power issue has been solved in an excellent way by using the ipod 30pin connector (which does require an ipod or an iphone)..

a few reviews here;