Want to get some decent headphones for my i-pod.I travel alot, is it worth getting noise cancelling?

Noise cancelling headphones are wonderful for planes etc. but there is a trade off against overall sound quality per pound spent. To achieve the same level of audio quality you will need to spend approx. 60% more than a standard headphone.

If you don't want to go down the cancellation route then consider a "closed" phone as the amount of external pollution is reduced greatly.
You pay for what you get.