I have never seen or heard of anyone use P2P software for anything other than illegally downloading and sharing music and films. If the recent court ruling does result in a blow to the P2P networks then I don't honestly have much sympathy with the users, who have clearly brought it upon themselves. Most people now seem to think that they have an inalienable right to free content via their internet connection (as if some proportion of the money they pay their ISP actually went to the copyright holders).
One girl I spoke to the other day said to me that she needed the internet because she 'does a lot of downloading'. I can only speculate what she downloads, but 10 to 1 it is copyrighted music.