I think Federer whould win. He is not playing his best, but there is no one else who is playing too good. I have a feeling that this year will be a "Lost year" in Men's tennis as I do not see any great rivalry coming up. Neither do I see many hard fought high class matches.
Of course, if Nadal and others like Djokovic, Murray and Davedenko come up, it will be great, but I think that will be more like 2011.