Only one town hall format, with prescreened questions. All three debates do ot allow the candidates to even look at each other, and they cannot directly address each other.

According to [link|http://www.cnn.com/2004/ALLPOLITICS/09/20/presidential.debates/index.html|this CNN article] one of the sticking points was that the Duh camp didn't want a town hall forum at all (figures):
According to sources familiar with the negotiations, the Bush team initially wanted just two debates, skipping the town hall forum in Missouri.