Half Life, I'm amazed no one else has said that yet. What kind of ending for the series was Ep. 2?
...
Kidding (please don't kill me)
Stargate Universe immediately takes top honors for me. Firefly was so well wrapped up by Serenity I don't feel as bad about it, in a lot of ways I actually liked it more then the show itself. SGU on the other hand, the last episode is fantastic as an ambiguous ending but that still doesn't change the fact that it's a massive cliffhanger. I want to find out what the signal is damn it!
It's a shame Dollhouse couldn't have hung around longer but like with Firefly at least it got a good conclusion.
Other noteworthy things include SW: Battlefront, Enslaved (probably), Better Off Ted, and potentially Torchwood since no one seems to know what's going on there.
Oh, and Silent Hill. I mean, the last game came out in 2004, you think they would have tried to make another one by now. Could you imagine how great a Silent Hill game on current-gen hardware would be, there's no way that could go wrong... right? ...Right?