I agree about the Consul in The Sweeney. Got to be the most defining car used in any TV programme.
Also, the car used by Starsky and Hutch, and the car Kojak had with the magnetic red flashing light. The big American cars always looked impressive, all that body roll when being driven hard in a car chase.
I'm going to say this once, and once only Gene. Stay out of Camberwick Green!
The 'Sweeney' Consul NHK 295M has always been a favourite but for me it's the Aston DBS and Ferrari Dino 246GT from 'The Persuaders' which both top my list. The Dino still lives in Italy but apparently the owner isn't the slightest bit interested in its early TV background, and the Aston sold at auction last year for £550,000!
Another one high on the list is the Rover P5B Coupe used as the main car in 'Villain', reg. number HXC 802H, which also appeared in an episode of 'The Persuaders'.