1 It depends on how smart the AQ strategists are.    A Republican victory is (in my view) beneficial for them, because Bush's policies give them traction in the Moslem world.  George Bush has been the best recruiter AQ has had in the last eight years, and they are going to miss him.
A Democratic victory, on the other hand, will result in removal of the lot of the irritants that AQ propanganda can fuel itself it on.

Therefore, from the AQ perspective, reduced US combat deaths are good in the short term, and lack of terrorist successes inside the US are good, because that will be seen as evidence the efforts of the Bush administration are actually working.  Best of all will be a terrorist plot interrupted by the Bush administration. (I think it certain the AQ higher ups would purposely betray a cell here in the US if they feel it serves their overall purpose.)  A successful terrorist attack, OTOH, would be a roll of the dice.  It might be seen as proof that Bush has failed in the war on terror; or it might be the catalyst for a response similar to what happened after 9/11,for people to decide they need the Republicans to be sure that the US is tough on AQ;  and it would probably provoke people around the world to turn more sympathetic to the  US, which AQ definitely does not want. 

So I would predict a lull in AQ sponsored terrorism during September or October.  Of course that assumes that the appropriate people in AQ are as intelligent as me

2 The "Bush Doctrine as Recruiting Tool" is not an accurate meme.  Yes, they do use it with some occasional success, but far more are turning away from extremism.  Look at Anbar Province in Iraq, the Iranian dissident movement, pro-American leaders elected in France and Germany, and the despairing tone of intercepted communications recently.  They do not want a Republican in office.

Fortunately, they're not as smart as you and are unable to exploit the majority of their strategies.  They lucked out in Spain and Spain is paying the price for that.  Their appeasement of Islamic Radicals was an attempt to avoid further acts of terrorism... it hasn't quite worked out that way.  Look for Spain and most of the EU to become more pro-US because the Islamic Radicals have become a huge problem for them.

3 Stash is right, the "Bush is causing more jihadi recruiting" meme is inaccurate, people have to think they have a chance at winning or they're much less likely to go to battle, and the jihadis are aching for recruits.  Terrorism and guerrilla warfare are heavily reliant on a favorable political climate and a large number of willing recruits. 

The crappy recruiting pool the jihadis have is evidence that they are in bad shape.  When they're using children and mentally handicapped people as bombers, most people are going to be horrified/disgusted by it, and the jihadis hurt themselves politically, which then defeats the whole purpose of terrorism/guerrilla warfare.