There's so many.... My favorite(s) would have to be the AMT "Trophy" kits from 67-68. The 64 Galaxie Daytona special stands out.
Favorite box art/worst kit would have to be Revell's original issue 57 Nomad. This car was featured on the cover of the May(?) 67 Rod & Custom. I can't recall the name of the the owner but Dennis Ricklifs striped the beautiful flames.
The car had Skylark wires on it. If you have a original box look closely at the wheels. The car is in color on the box, but has b/w chrome reverse superimposed on the car. The art work had already been approved by Revell, but the wheel difference wasn't noticed untill it was too late. Some body at (Jim Keeler?) Revell went out to the parking lot and found a car with chrome reverse wheels on them, took a picture, and they were "mounted" on the box art car.