Not a bad episode, which is about as good as it gets.
My theory that I mentioned before about the flashforwards being from a parallel world rather than earths own future now has an explination thats more or less laid out in the show.
Their american cern was turned on at the moment of the blackout 6/10/09.
Pennys english boyfriend said about the other worlds theory, where things are almost identicle.
So what if the other worlds US cern was turned on 21/4/10 because of some technical or political delay?
The two then created a wormhole that linked both worlds, one having a flash forward, and one a flash back.
Which would explain how you get flashforwards for dead people, or none for others that probably wont die in this world, how people are together who wont be, and how noone ever goes "hey, Im in my flashforward!"
The only thing it dosnt really explain is Marks mosiac board