I don't need to say more than a few words about this to make my opinion perfectly clear:
Assassin's Creed 2 launch. Diablo 3 launch.
There you go, argument made. Two single player games that were utterly BORKED on launch day, and in AC2's case for weeks, for legitimate customers, while pirates laughed all the way to the end of the game. When a game's method of DRM hurts no one but the legit customer, something is horribly wrong. I don't mind a one time activation online. What I do mind is DRM that actively counteracts my possibility as a customer to enjoy the game.
My latest pet-peeve is SimCity(5). SimCity has always been a single player experience and always will be. Simcity 2000 had an experimental network version that didn't really work too well. If I wanted multiplayer, I would've played something else.
Now, I don't mind the option of multiplayer. It's nice that it's there, but don't shove it down my throat. Or would you rather be forced to play AI:War in multiplayer? It's the same thing. A single player game that can be played in multiplayer. This whole forced, always online, multiplayer thing is nothing but a very thinly veiled DRM. Also, see Timmy's "Old games" argument. I'm currently enjoying Master of Orion 2 (on my phone no less) and Total Annihilation. If they carried this kind of DRM, I wouldn't have been able to play them, because their servers would be down by now.
And now you got me ranting. Thank you very much.