Kristen,
I liked the 66/69 Chevelles, but like mentioned above, check for rust and other things. The 69 MUST have the 454 engine in it.
Try to talk him into a 1964 Ford Fairlane Thuindebolt. Only 100 made and they are really something. That way he gets invited to all of the major Ford shows.
GTOs were great cars but just never really captured my interest. Very fast and had a selection of motors. Bad, Badder and Blown!
The there was another of my favorites. The Hemi Cudas and Chargers.
Ron