Rasmussen has a 3 day tracking poll. So does Gallup. They should have similar trends. They do not. Rasmussen, Hotline, ABC/WaPo are going one way (Obama), and Gallup, Zogby, Battleground, and several newspapers are going another (McCain). Most of these polls followed a similar pattern in 2004.
Catowner,
ABC/WaPo has already been analyzed and debunked as an outlier. They oversampled dems by 16% (vs 3% actual over the last 4-5 elections), and oversampled African Americans by 6%.
Rasmussen seems to lag.
Batteground is one of the best since it is done by BOTH a democratic and republican pollster.
Regardless, national polls do not matter. Better off to look at state polls, which unfortunately are less frequent and have a larger MOE.
What is really the thing to look at is the internals and demographics of the polls. McCain is winning almost every demographic profile. Women, Catholics, Independants, and even younger voters have shift to McCain the last month.
Obama peaked in February, and has not made any progress in expanding his voter demographics since that time.