If i like an album i will most probably buy it, because i don't like many albums. Only rap, and being where i am i can rarely find any rap albums except really popular stuff like Eminem, D12 and shit. Sometimes the quality of a leaked version varies, and sometimes it's just nice to actually have the CD.
You can find most songs on video websites to videos of like Naruto (and what exactly does Eminem's beef song Quitter aimed at Everlast have to do with japanese anime about a ninja?

) or some shit like that anyways half the time, so i do that sometimes too.
I don't think they should stop leaking though, there's people who can't afford to buy every album they like.