I'm not sure how I feel about P2P sharing, my views tend to differ depending on the situation. Most people I know have only ever downloaded/borrowed a CD from someone if they dont like the artist but think, "what the hell, i'll check their stuff anyway" or genuinely have no money at that time to buy it, but then go out and purchase it when they do.
I don't think established artists should get too caught up over royalties from released material in certain circumstances as it can serve as a great tool for promotion - someone who doesn't usually like your material could download it, like it and as a result recommend you to others who then go on to purchase it. Not to mention people in countries suffering from war and political problems who honestly can't spare the £12.99 to buy an album, which would mean weeks or even months of going without food... as long as they are enjoying your music you've done what you set out to do. BUT people who can afford it, but just abuse it for the sake of it are plain old b'stards!
Having said that, record companies are just as bad as bootleggers themselves. When the initial popularity of the net set in and it became apparent that people were using it to seek out hard to find music and sharing material, instead of sitting on their arses worrying about losing money they should have made the music available to download at a price. If they had thought logically they would've seen earlier that legal downloads are more beneficial to them than units being sold in the retail market - there are no distribution costs and world-wide promotion is thrown in for free. You only have to look at how i-Tunes has taken off to know that this is what people have been crying out for, mp3s are selling more than actual singles in shops!!
Illegal downloading of underground material which goes on to jeopardise sales before they've even had the chance to get somewhere really riles me though.