Who will win?

The results are starting to come in as I write. I have I think spoken about this before but I still find it amazing that while the polls are still open here on the west coast of America results are being called on the east coast. Surely this could effect how people would vote out here in the west? I guess I am used to the British system of actually waiting until all the votes have actually been counted before determing who has won, unlike here where it seems to be a mixture of exit polls, gut feeling and random guessing.