I have yet to see or hear anyone mention that Bush looked at the camera a lot more often than did John Kerry, except during the closing statements. I wondered afterward if this was an intentional move of the Kerry camp, trying to "save the best for last," so to speak. But more likely, Kerry just didn't remember to look up into the camera--it's too bad for him, because a major goal was to present him as a kind of person people should trust, and like.
For all the people that can't stand Bush's style, there are an equal number of people who are put at ease by his folksiness. Though Kerry isn't ever going to appear as down-home neigborly as Bush does to some people, he still could appear more approachable than he has. That could happen by showing a little bit of humor, but the subject matter last night wouldn't allow that. His lack of "eye contact" with the TV audience obviously didn't ruin his performance, as polls seem to indicate a slight win for Kerry.
But people often have a hard time looking you in the eye when they aren't telling the truth or aren't sure what to say, and this perception could reinforce, subliminally, some voters' questions about Kerry's consistency. Bush came across as sincere in part because (ironically) he looked at the camera so much. Kerry certainly didn't appear insincere, but he'd appear more personable if he looked at the camera, too.
Overall, though, it was a good debate, for both candidates, I think.