Today EMI announced that they will be selling non DRM music. In fact, their entire catalogue will be availble in an "unencumbered" format
for a price. There's a BBC story about this
here
This is a highly symbolic move and we won't rehearse the pro/anti-DRM arguments again. The interesting thing for me is that it is not actually much of a big deal for EMI. They already sell unencumbered content in the form of CD's. The price of 99p (UK prices) per track works about about the same as a chart CD [yes, CD's are a rip-off in the UK - maybe that's why they get ripped so often - sorry, couldn't resist the cheap pun

]
So, I don't think that this makes much short term difference to EMI. I guess that the price of a CD has an informal mark-up to pay for the extra copies that users make for the PC, MP3 player, car, friends, etc. All that EMI have done is move that model online, and therefore reduce their distribution costs.
What EMI might have done in the long term is the kill the (content aggregators') dream of locking up content so that users have to pay for every single copy, but I think that that was probably always a dream. If EMI can establish themselves as a trustworthy, friendly aggregator of music then their business model might last for a long time even if some fans get their music free. Actually, even if 90% of fans get music free!
What about movies? If the "non DRM" model becomes the standard, will Hollywood be able to keep its own content locked up? They do have an advandtage as DVDs do have enough protection to stop some users ripping them. On the other hand, I think they are swimming against the tide here. The big problem for Hollywood is maintaining the system of "release windows" in the face of non DRM copies circulating. I have never really understood why release windows have to be staggered around the globe and maybe they won't be in an non DRM future......