Such a difficult question to answer, as my all time favourite top 3 keeps changing. At the moment it would have to be, in no particular order;
1) Jaguar mk2 3.8. I know all the world loves the E-type, but to me the quintessential Jag is the mark 2. Carmen Red with red leather and wire wheels. Sadly I've never owned one. An older friend used to run them as everyday cars in the late 70s when you could buy a scruffy one with 6 months MOT for less than £200. Happy days...
2) 1965-6 Sunbeam Rapier Series 5. Not an obvious choice, but I've always loved Rootes Group cars. My dad had Rapier as a loan car for a couple of days when I was about 8 and I fell in love with them. The pillarless windows were just so cool. I eventually bought a Series 5 as a hobby car. Of all the 60 odd cars I've owned, it's amongst the very few I really miss. The maroon one in the pic was mine.
3) Ferrari Daytona. Such a beautiful shape and a true supercar. Never thought I'd get near one until a customer at the flying school my wife worked at turned up in one. Red with cream interior. Once I'd finished dribbling all over it, he asked me if I wanted to drive it. At urban road speeds it was like driving a truck. Heavy steering and clunky gearchange. He reckoned that it came alive at around 70mph. I'll never forget the ride though....
Others in contention would include the Citroen DS, the Fiat 130 saloon, the early 1970s Toyota Crown and the 1964 Buick Riviera (who didn't have the Corgi Toys model of it?)