Hmm... I would definitely put Light, L, Near and Mikami in the 180-200 range, and Mello in the 150-170 range. I could see Light and, to a lesser extent L probably at or above 200 for immeasureable genius. Mikami is probably in the 190's, and Near is probably in the 180's. Hmm, Near is my fave character, yet I put him at the next to lowest IQ. Yet he's the only one to survive out of these characters, LOL.