This topic has been debated extensively and a trend I'm seeing is articles saying that pirates buy more media then people who don't. I see this to be true in my friends too, for example one guy I know has around 80 gigs of pirated music and owns 500 cds. How many people do you know who own 500 cds? I don't know many.
Im with ekmeister, theres this same argument on every 'underground' band's page. Like you're the reason why bands break up because you didn't buy their cd's. I got Junebug in the mail today because the rip sucked so much balls that I wanted to hear the real deal. I paid too much money for it though. The album and their first both kick a lot of ass mind you!
No it doesn't matter one bit if I download it or don't buy it. Because I won't buy it. If I download it, I will listen to it, and might like it alot. I might go to a show some time or buy some merch or whatever. The difference lies where the music reaches out to more people. That's how I would see it if I made music. Maybe I'm just being silly but that's my opinion. Sure I buy some CDs, but they have to mean a whole lot to me before I do so. And yes I'm sure you've bought a CD of all those 2400 artists in your library. Fuck I just asked politely if someone felt like sharing it.
Because this band needs press and some exposure to have money to afford to travel and go to shows, and if only 500 people buy their album, they won't have the buzz to make that happen. Fine, you're only one person, but i promise you that 10 times as many people steal this album than purchase it. So, it matters.