To honest, answering that question is a little like a father saying which of his children is his favourite! 
But after much deliberation, I'd have to say that I'm most fond of the shape of the '65, followed by the '67, and finally the '64. The '65 is a beautiful, timelessly elegant shape, which looks gorgeous and modern, despite being close to 50 years old. The '67 is similar, side on, but is just a notch below the clean, fluid grace of the '65, although it's MUCH more "ghetto"! The '64 is a beautiful shape, too...but just doesn't match up to the former two.
Another reason why I'm so fond of the '65 is sentimental reasons. My old man (may Allah rest his soul) was a great car enthusiast, too. He'd never lose an opportunity to tell me, that when I was born (Sept 1966) I travelled back home from the hospital in my Dad's pewter-grey '65 Impala. Owning a ride like that, with the assorted memories, has it's own peculiar pleasure.
Finally, the '65 has been the recipient of a lot of TLC from me. The flame paint, the interior design, the sound system, the engine choice, and the exhaust note are all things which I've been intricately involved in. The fact that it's reliable (thank Allah), terrifyingly quick, and an absolute blast, make it all that much more worthwhile.
