Swing States
The closest states on the Intrade prediction market are currently Ohio, Nevada, and Virginia, with the latter two being fairly close since ElectoralMap.net began tracking prices in late May. Nevada traded right on the razor's edge, nearly 50/50, until the conventions stirred things up a little. Ohio was trading strongly in Barack Obama's favor until late August. The conventions and the Palin nomination seem to have favored McCain, as it's a virtual tie now.
Pseudo Swing States
States like Colorado and New Hampshire have, at times, trended towards tossup territory. It's hard to look at their graphs and call them true swing states, though. Both seem to favor Obama at least 60/40.
Wish List States
Although the candidates like to spend money and time in states like Florida and Pennsylvania, Intrade would call this a futile effort. According to Intraders, Obama's lock on PA is even stronger than McCain's lock on Florida.
2004 Campaign TV Advertising Expenditures & Visits
Courtesy of Wikipedia, every dollar sign represents one million dollars spent by the Bush and Kerry capaigns in 2004 on TV ads in the final five weeks of the campaign. Every hand represents a visit from the candidate, or their VP, in the final five weeks of the campaign.
