In this election season the undecided vote is somewhere around 10% at the most. Everyone else is pretty rock solid in their chose of candidates. Having said this the only way Kerry would see some of the historical bumps you've listed is if all the undecided suddenly became decided because of what they saw from him at the convention or the resulting good press the liberal media is giving him. So a 4% bump in my opinion isn't as bad as some are making out. The real question is will he be able to maintain the bump till election day? I say no!
"In this election season the undecided vote is somewhere around 10% at the most. Everyone else is pretty rock solid in their chose of candidates."
-- Eytime I hear this crap it makes me sick; It's all about turnout. Partisans show up at the polls in much higher numbers than independents. If Al Gore increased turnout among registered Democrats in Florida by 1%, he would have won.