Well, you could go one of two ways:
1) You could say absolutely, and state what makes the school's program that's interviewing you tops in your mind. Or...
2) You could be honest, and say that you will weigh all of your options carefully, but point out what sticks in your mind about the school that your currently interviewing with.
Really, it depends on how you feel about the school, and whether or not you have other options available to you.
I would definately say it's probably easier to be honest and positive. By all means, if you love the school, make sure that if given the chance, that you make that clear, though.
Whatever you do, don't say, "Nah, I don't think this schools the place for me." What if it's your only option?
Oh well, now you've heard from the people who give me advice and float on my shoulder like in the movies. Only, I have a whole team of advice-givers up there. Usually, there's not enough room for all of them, so I listen to the voices in my head a lot too, but I guess that's another story.