I was so annoyed that Hiro didn't have the sense to immediately, after stabbing Sylar with his sword, to cut off his head. Everyone knows that to make sure to kill a villain, you cut off his head, and then burn the body for good measure. How dumb. And no one seemed to take any notice of Sylar whatsoever. He was able to crawl (and I assume slowly from the blood trail) to the sewer and get under without any opposition. He knows exactly what he needs to do now to be President.
Which brings me back to Peter. We're assuming he survives because when Hiro went to the future, Peter was there and I can't remember who, but someone indicated that he was the real bomb, and not Sylar. So if he had been the one to explode and survived, then I doubt he didn't this time (esp. since he can fly and regenerate).
So Peter survives. Tell me, what will prevent Peter from blowing up later? In the vision of Peter exploding, he was in a very busy area of the city during the day. There were lots of cars around him and the other heroes were running away from him. Not like in last night's episode, where it was night, hardly anyone was around, and the heroes were standing there watching. This worries me. I know Nathan wanted to save Peter and everyone by sacrificing himself (assuming he was not able to get away before the explosion), but it may have been worthless. If Peter comes back the next day and explodes, then Nathan won't be dead long enough for Sylar not to take over (for people to know Nathan died). I'm sure Sylar knows where Candice is and will take her ability while she's still unconscious and replace Nathan. Maybe Peter won't even realize because he'll want to believe Nathan didn't die.
It seems to me that Peter's inability to control going nuclear is because Peter is a very emotional being, and when his emotions flare, so does his nuclear powers. Sylar, on the other hand, seems very unemotional, which is why he's able to easily control going nuclear. Ted had to go through a lot before he was able to control it. So I think this is why Peter goes to drinking and such in the future and seems much more cold. Just a thought.
And I agree with Fell about Candice not reverting to her true form. I was thinking the same thing.