Seen this question when at collage...been thinking about it all day! This Is all my opinion, so no wars over why I'm 'wrong' and such.
Now The choice has to be something classic, as although most modern cars look nice there is something about cars from the past, the sort of organic curves. Not only that, but the car has to have a 'soul', having been handmade. This also rules out modern day cars, most of which are made on peopleless production lines, or the lines resemble laboratory, bright and clean. the car also has to have something that makes it stick in my mind as well, all nice in having something looking great..but if I can't remember how it looks in my mind to 90% then was it really that good? What the cars are made of as well, but I find what the car was made from has an effect as well, I don't know how to describe it, but the 'shine effect' you get off some classic cars when viewed in the right view has a huge effect!
So with this in mind, the short list consisted of the Ferrari 250 Lusso, The Aston Martin DB5, The Jaguar E-type, the MGA Twin Cam and the Lotus 7. But there could only be 1 Winner...
http://i189.photobucket.com/albums/z23/calster-17/Car%20Pictures/Lamborghini_Miura_Bible.jpg
"On days like these"
:D