I have a similar dilemma. On the one hand, I am an American League fan of an American League team, and after blowing up the Death Star the other night the Detroit Skywalkers have earned my eternal gratitude.
On the other hand, my girlfriend and her entire family are Mets fans. So much so that her father, through his company, has a skybox suite at Shea. If the Mets go to the Series, I will likely get to go to a World Series game for the first time since 1991. If the Mets actually win, not only do my immediate-term prospects for a good evening improve dramatically, but the long-term prospects of getting my girlfriend more into baseball and more willing to go to games also improve dramatically.
My heart says vote Tigers. My head says vote Mets.
Well, it may become academic if neither team gets past the next round. I kinda think the As' pitching is just as good as the Tigers', and if Pujols gets hot, he could match Beltran. The Mets' starting pitching is in flux at the moment, but the Cardinals' is no better.
And, as we've seen, teams can just plain go cold. The Yankees couldn't get hits with runners in scoring position, and neither could the Padres.