I’ve had a few rants on this blog about why DRM-protected consumer goods (i.e. music and video) are A Bad Thing (e.g. here and here) but this comic from xkcd.com really makes a good point (which Walmart customers will appreciate – even if the company did later decide to keep the DRM servers running, how long can they be expected to do so for?):

(This comic is licensed under a Creative Commons Attribution-NonCommercial 2.5 License.)

For UK downloaders looking for DRM-free music, I recommend 7digital (but have no affiliation with them).