I stepped back, because I don't want to get too long winded, as I always seem to with this kind of stuff. For me, it just comes down to a respect of someone's work. I think we'd all revolt if our respective employers came to us and said "We've decided to hold your check this week until we see if we end up liking the work you did. It may take us numerous times of trying out the project you were doing before we decide if we'll pay you for it or not. It may even take months to know. Actually, we may just end up using your work for ever, and entirely forget to getting around to paying you for it."
Yet we (I say "we" loosely, and any and everyone on here who knows me knows that I am ridiculously anal about buying albums, or only downloading things legally) do that to the industry and artists we're supposedly fans of every time a leak is downloaded, a full album is stolen, etc.
There are soooo many ways to hear music legally. Artists and labels truly go out of their way these days to provide opportunities to hear their work. Streams or mp3s on their site, the label's site, Myspace, official Youtube channels, Last FM, etc, etc, etc. The idea that we can't get enough "samples' to know in advance if you want to purchase something seems selfish and a bit silly to me. If specific reasoning NEVER applies in any other industry, why do people think it's relevant or justified in entertainment?