Best Buy has purchased the once-pioneering, now-also-running digital-music service Napster for $54 million, or $77.14 per subscriber to the service. The folks at Marketwatch are theorizing that this move was made in part to jumpstart the electronics retailer’s digital-music strategy–currently, anyone who wants to get music from BestBuy.com has to go through a kludgey, Windows-only version of Rhapsody, so I guess Napster would be a huge upgrade–but one poster on the Velvet Rope smartly points out that Napster’s overall download infrastructure will also help the retailer shift its distribution of, say, software from the big, clunky boxes that take up valuable shelf space to bits of data transmitted over the Internet. [Marketwatch]