Whether it was the black and gold JPS or the red and gold "Gold Leaf Team Lotus" colours, the Lotus 72 was for me the car that will always be what a Formula 1 car should look like. When I watch historic F1 races I still think that car just looks fantastic. As you say, Brian, if you look at the other cars which were racing at that time, Chapman was a hell of a visionary, even if his experiments killed off a few of my heroes!
The other pretty impressive looking car was the "flat" Brabham BT55 which BMW built a special flat engine for. Lauda refused to drive it because it was on a "pay per point" basis, and after seeing Derek Warwick do a double backwards flip in it in practice in Austria I think he probably made the right decision :-) As for the various 6 wheelers - exciting to look at but not pretty by any means.