Hmm, a difficult one! All these relate to intelligence but don't quit hit the nail on the head, but of course that's understandable.
I like Stoop's model the most, it's nicely detailed and complete. Tictac's shares a similar idea; tool of intelligence. Wizard's is a nice and simple idea, and a very neat model. RawMeat's is also a very good idea, but harder to pull off as effectively. I really liked MuffinKing's the first time I saw it, mainly because of the pose but also because of the style of the polygons. It's probably the hardest to model and pull off as well, so good work!
Seeing as I can only vote for one, I'm going to vote for Stoop's as I think it's the best compromise between a good model for a speed challenge and an idea relevant to the theme, however all models and ideas are very good :)
Keep up the good work guys.