I've had a general policy of not buying games for any platform if their PC version requires an always-on connection (aside from MMOs, which it would be unfair to penalise, as "always on" is the very nature of the game there). This means I've missed out on every Assassin's Creed game since the original and a few other titles to boot.
I agonised about Diablo 3. It did look, at face value, like a straightforward case of Ubisoft-style DRM. However, Blizzard did push quite hard the line that the game had integral features that meant they couldn't have done it without the always-on without making serious compromises to the game. I was... unconvinced. So I decided to wait and see how things went at launch.
As it happens, Blizzard then wheeled out that "subscribe to WoW for a year get Diablo 3 free" thing at just about the time when I was in the market to get back into an MMO. On balance, I decided that I might as well go for that.
Now that I've had a few hours with Diablo 3, I can conclude that if it hadn't been for the WoW special offer, this would still have been firmly in the "boycott" camp. I've yet to see any online features that could not have been made 100% optional at no expense to the player (though possibly at some expense to Blizzard through lost real-money auction house fees). If you're in the "undecided" camp on D3 over its DRM, my advice would be to avoid it.
This is exactly the kind of reasons, along with price, that I'm going into the Torchlight 2 camp.
