From what I've seen of Sarko in the last few days, he seems rather tired (or am I imagining things?), whereas Royal seems more relaxed. Though I base that on whatever I've happened to see of the two on TV lately. I'm hoping tired Sarkozy shows up for the debate tonight, though probably not.
Anyway, I don't know how much of an impact the debate ultimately will have on the election, but in light of the still fairly large gap between Royal and Sarkozy, she'd better kick his ass. "The basis of optimism is sheer terror" - Oscar Wilde
If Royal comes across as clear headed, intelligent and commanding; she has a very good chance of winning the election as at least 25% of the voters are undecided, should be a huge turnout with the election so close, and her discussion with Bayrou will help her in addition to LePen asking his voters to abstain.
I am not sure I trust any polling coming out of the major polling orgs because you dont know whether their polling is unbiased.
It also ignores media support for Sarkozy. Even if Royal wipes the floor with him you can expect some put-downs and spin from the right wing press.
It's not over yet, but it looks a bit too rabbit and hat for comfort at the moment.