I agree with ElevenProdigy above about the production of season 2 so far.
As for who dies, I am sure that Hiro will not - we know from the plot that Matt, Hiro, Adam, and Peter will face at Primatech. Just when Peter says (in the preview) "let's go destroy the virus" and adam is seen to resume from the time-freeze, Matt will show up. Don't forget that Matt has the new mind-control ability and he will use it, I suppose, to find out more from Adam or force something out of him.
Nikki will die as she will try to save Monica.
In the preview it says that a villain will rise so I would say that would be either Sylar or even Peter (becoming a villain as he trusts Adam). But in the preview we see blood in Sylar's face and his attempt at controlling objects with his hand stretched; he's also lying down against a wall looking as if he's shot. This is the point where I think Elle will be "daddy's favourite" again - she will come at Mohinder's aid. And besides, I think the producers realise that Sylar should be out of the picture by now (he's killed too many and Alejandro was too easily taken).
So Nikki and Sylar for me.
