Sylar's going to live... the city is going to blow up, and the series is going to continue.
There has to be a bad guy. I think the glimpse into the future a couple weeks back is basically going to turn into reality. Sylar is going to kill Candace the chameleon, be able to imitate Nathan, possibly killing him too. How messed up would it be if Sylar were actually the President? I just don't know who else would be the antagonist if Sylar ended up dying. I can imagine Hiro and Peter chasing after him for a long time.
I was kind of glad Ted the nuclear guy died. He was annoying. I was okay with Linderman dying too, he didn't add very much. Although, it could lead to Nathan trying to avenge him, since he helped his wife walk again. I didn't like seeing DL die though.
Heroes has already been picked up for another 24 episodes. That was done back in January. And apparently there's already a spin off series.... Heroes: Origins has been picked up for 6 episodes. That apparently is going to introduce a new character every week, and "voters will select who stays for the following season." hmmm. don't know about that, but sounds like they're at least in for next season.