Peter Cullen brought Optimus Prime to life. He attributed that pitch-perfect voice to his brother's pre-audition advice: “Don't be one of those Hollywood heroes. Be strong enough to be gentle.” It's safe to say that he got that right.
I've been a life-long Decepticon but I'm surrounded by Optimus Primes purely because he was an icon, and much of that was the sound as well as the look. (I was even represented by Optimus Prime in the one occasion that we produced a family Christmas card, despite my allegiance to the other side.)
(Edit: Sorry, Jazzy. I was typing whilst you were posting the same thing.)
