Watched it last night. Seeing archival footage of George W. Bush and Karl Rove was very enlightening. You can see echoes of Atwater tactics in every later campaign, up to and including McCain's campaign.
What's intriguing is the way the Obama campaign designed itself to counter Atwater-style attack politics. The whole "politics of hope vs. politics of fear" concept was designed to fight back in a relatively positive way. In particular, the Obama people would not just deny misinformation, but they'd attack the messenger for putting out negative information. Likewise, they were clearly ready with tit-for-tat responses. You smear us, we'll smear you.
According to the documentary, Atwater has no compunction against bold lies to tarnish his opponents and screw with their heads. You can actually see some of this going on even now, post-election. Example: the "we're still a center-right country" theme, implying somehow that Obama shouldn't push too hard on undoing the right-leaning policies put in place in the Bush administration.
My head's been spinning all morning, trying to look at the McCain/Obama race through the lens at Atwater-style tactics and counter-tactics. Fascinating stuff.