The decreasing costs associated with hard drive space is already changing the way we do business on the web (see photo sharing sites and web email for a couple of examples).
But the availibility of cheap hard drive space will go beyond the web and entirely change the way we consume media.
There are already market research companies that record everything that comes over a television cable, every channel, all day, every day.
Soon, consumers will have more access to these large hard drives. And if you have TiVo or another DVR, you can already see that having a big hard drive where you can save stuff changes everything.
Now these recording devices and business models are set to to hit the music business.