Here is John McIntyre's of RealClearPolitics.com guide to election Night in the Pennsylvania Primary which I agree with.
Here is a quick guide to sort through the inevitable post-PA spin.
--Obama wins: Race is totally over.
--Clinton wins by 5 or less: Race is effectively over.
--Clinton wins by 6-9: Status quo, which favors the front runner Obama, particularly as the clock winds down.
--Clinton wins by 10-13: Clinton remains the underdog, but her odds of being the nominee will be considerably higher than the conventional wisdom in the media.
--Clinton wins by 14+: Totally different race, as Clinton will be on a path to claim a popular vote win that will give her every bit as much of an argument as the legitimate "winner". In this scenario anything could ultimately happen, including neither Clinton nor Obama becoming the eventual nominee.
This reminds me of when I watch a football game in which I am not a fan of either team. I tend to root for the underdog until that team get a lead in the score then I start rooting for the other team. I started out rooting for Obama in the early presidential primaries and now I am rooting for Hillary.
Get the popcorn ready. Politics is so much fun!