You've perhaps thought about giving somebody a subscription to Netflix or Hulu for the holidays. That is incorrect. What you're buying them is a gnawing anxiety about the sorry state of their queue — the Kurosawa films and documentaries left unwatched as they tear into episode after episode of The Real Housewives of Wherever — or a steady constant ache that there's never anything to watch because the selection is so limited.
A music subscription, however, is a golden ticket: unlimited access to basically the entirety of modern recorded music, since the catalogs of Spotify and Rdio contain literally millions of tracks. And everybody listens to music. Even horrible people. Maybe you're a junkie that incessantly craves new music, twitchily moving from one band you've never heard of to the next. Or maybe you just listen to the same dusty tracks over and over again. It doesn't matter; Spotify and Rdio subscriptions work perfectly in either situation.
Also, can you watch Netflix while you run? Or work? Or drive? Or have sex? Or ride the subway? Maybe, but then what you really want for Christmas is to incur serious injury or death and I feel real bad for you. You can listen to music, however, almost everywhere, in basically any situation. I am doing it right now. It's pretty great, even if this song isn't.
For people who don't already have a bunch of friends using a music service and would simply want access to music, Spotify's the better choice. It's got the most exhaustive catalog, and upcoming features, like new ways to discover music, look pretty solid to boot. (Even if its app is unnecessarily ugly.) It's got one-month, three-month, six-month, and one-year options for gift subscriptions, all running $10 a month. Rdio has a better app and a much stronger social component, but the catalog is slightly smaller. It's similarly priced, at $10 a month.
Look at it this way: Perhaps what you're really giving the recipient isn't a tacky electronic gift card, but the gift of freedom, since it means he or she won't have to illegally download music and get sued for $600,000,000,000,000,000,000. Per track. I know I really hate it when that happens.