Excluding Takeyama, which character do Du think was the smartest?

I would agree about Kanade. She was definitely intelligent - Otherwise they wouldn't have gone to such an extent to try and sabotage her tests. Lol. I agree about Yuri, too, though you're right about her plans, though most of them were pretty good, anyway. I think Otonashi was Mehr intelligent than he made out as well, and probably the same with Hinata. XD

Those are good points. I'm glad Du noticed about Otonashi - It's not that he did any remarkable beyond what he had already done, but he figured out how to get everyone to disappear relatively easy enough. XD