Not sure what the legality behind it is. I'm not a fair use expert. The music industry hasn't been behaving fairly of late, so you can hardly expect consumers to do so either.

It's not something I would do, though. Did he rip the discs losslessly? How sure is he about his backup methods? For me, CDs represent a compact, relatively durable backup system that I don't even have to think about. Not only that, CDs are an easy way of supporting a local music store, which is basically impossible when you're buying online. And my CDs are DRM-free, so I can go back and rip them to another future format, as many times as I like.

Now, that said, I don't display my CDs anywhere anymore. I'm currently in the process of moving them all to archival sleeves in small boxes in my closet, where they will likely live for the foreseeable future. Having the computer-stereo connection allows me to have a living-room with fewer and fewer obtrustive pieces of electronic ephemera.