There is no doubt that the MSM is the biggest winner. The WP, NYT, and shows like MTP, which highlighted specific Senate races important for the Dems, played a major role in shaping political opinion. I would toss in the late night comedians who have constantly portrayed Bush as a dunce and the war in Iraq as a mistake. It is a steady drumbeat wrapped in different packages.
I'd also add all the alphabet morning programs, and news magazines to the cable news, network news, Imus, the Daily Show, the View. All combined, it's still pervasive. Sad to say, but true. Turn 'em off.