There is something highly intangible that is missing for me - the joy of buying music and holding it in your hand. It started leaving once MP3s got popular, but at least you had a file. Now, if the trend continues, it's going to be music on demand, whatever you want, when you want it.
Yes it sound really great, as long as they is space there for the little artists, the obscure guys that the major record labels don't want to give time to. What about artists like Negativland, Emergency Broadcast Network, Synergy and The Enid - if all we have as options is listening to whatever the mega-corporations decide we want to listen to, then it may well be a bad day for the small guy.