3 reasons I can think of to take AC headphones:
a. They are good to take on carriers like WestJet and Tango who dont give you free headphones.
b. They are good to keep if they have the removable 2 prong connector because they can be used as aircraft headphones and also as regular headphones
c. The 2 prong jack (if removable) is good to have so you can use your noise cancelling headphones on the plane.
[This message has been edited by fromYYZ_flyer (edited 05-12-2003).]