I think this opinion piece does a good job of stating the rather obvious reality of DRM encumbered music. It also links to Michael Robertson's (MP3.com/Linspire/SIPphone) blog so you can read his words uninterpreted.
Just to be clear, a few years ago I dipped my toe into the DRMed music pool, only to promptly burn my purchases to CD in CDA format which I found I could re-rip to whatever format or use I wanted. Luckily, my non-audiophile ears couldn't hear the difference between the re-rip and the original, but I can assure you that degradation does take place.
So I ask you, which would I rather buy? Would I buy a full or single non-DRMed CD that I can keep, play, or rip to the format of my choice. Or would I rather spend my money on a compressed DRMed, proprietary music file that is locked to one kind of player and that goes "poof" for any number of reasons, including upgrading hard drive. I did lose one music file that I got on a free coupon that way because I did not make the aforementioned back-up to CD. If I had paid for that track I'd have been ticked off.
Like the article says, when you buy DRMed music, you aren't buying it, you are renting it. Time that the music vendors start making it clear to folks.
For the record, I don't own any DRMed portable music players. All I have is my Palm PDA which holds about 5 to 10 hours of audio on its SD card. It does the job for me.