Apple USB Keyboard not working on 27" iMac (Intel Core i7)
Sorry this isn't really an answer but I can't post a photo in a comment.
I have a 27" iMac i7 as well, when I connect a Key Board/Mouse and an iPhone via USB in "System Information" I see this:
What do you see?
Note that the two USB ports are on different busses. Have you tried both of them? You mentioned that bluetooth works; do the other USB functions work (Card Reader, iSight Cam)?