A Familiar Campaign Battle Cry: The Press Likes the Other Guy Better

In the race for president, we see an unusual dynamic: the specter of dueling media darlings. Although Sen John McCain seems amazed and annoyed that the media are "in the tank" for Sen Barack Obama, McCain himself has enjoyed one of the coziest relationships with the news media for years. And although Sen Obama is receiving about twice the news coverage, Sen McCain's coverage seems to be more positive. What are readers/viewers to make of this? And why are the campaigns using up so much energy debating it?