I'm not sure Ayers has a lot of traction in a debate. Remember that these debates are presumably trying to reach undecided voters. Most of these undecideds idiots don't know who Ayers even is or who the Weathermen were. They also neither know nor care about Rezko. If McCain brings them up in a debate, he has to first educate the viewers as to what he is talking about.
If he wants to hit Obama with these guys, he has to do better than Bill O'Reilly, who merely asked general questions like "What about Ayers? What about Rezko? What about Rev. Wright?", giving Obama an easy out when he merely claimed he hardly knew the people in question. Rev. Wright has the most traction IMO because Obama and family attended the church for twenty years. Even if Obama tries to sidestep Wright, one can come back with Obama's own words in his self-adulatory autobiographies as to how important Wright was as a spiritual mentor and father-figure.
Of course, with these undecideds idiots, any such attack may come off as mean. I think McCain did well in the last debate by coming off as calm and reasoned. If, as many here have stated, this election is a referendum on Obama, then McCain may have gained ground in the last debate by appearing to be the guy to trust in the hard times to come.
Bring up Obama’s brother. If everybody learns about Obama’s brother, they won’t vote for him.