I pre-ordered MAG.
Played through as SVER, veteran'd, then went to Raven, got about half way there, got bored.
I got my moneys worth though, I was pleased.
Also used to play BF2142 a hell of a lot. Got my moneys worth and then some with that beast.
Sometimes I like to play multiplayer games, and provided that the gameplays solid I'm more than happy to pay for a game that has no single player.
EDIT - Forgot, I used to play unreal tournament quite a lot aswell. Yes, it has a single player, but it's barely worth noting. The entire experience with that game comes from the online play.