Illegal for sure, but make the punishment fit the crime, and burden of proof be on the media companies. At most, these people being sued should be liable for 2-3 copies of what they infringed. When someone steals a DVD from a shop, you don't make them liable for every copy in the store, and then some. You make them liable for exactly what they deprived you of. Most of these people downloading anymore are uploading incremental bits to various users. All those bits assembled into one piece barely make up 2-3 whole copies, and thats IF they aren't leaches (which is rare) who don't just dine & dash once they have what they want. At that, especially bit-torrent they can only prove you have a complete copy or not because your client only relays that info to them.
The punishment just needs to fit the crime, not be a life changing event because you downloaded the greatest trash single of the month.