I just got a baby iguana, my first :) and I can already tell he or she is quite an intelligent reptile, with loads of personality! I dont know if I can teach it any tricks, like a dog considering that they lack the ability to hear, but I am sure he is quite an intelligent animal.
There was an article in repitle usa I think about an iguana with many health problems. To be honest, once I read that article i knew I would one day buy an iguana. Altough this iguana was sick it had such personality and intelligence.
As a reptile lover, mostly turtles and lizards :), I will never let anyone tell me that tortoises and iguanas are not intelligent or lack personality!