What is the best kind of bread?
What is the best religion?
Who is you favorite Child?
Who is the worst boyband?
What criteria do you want to use when making this determination? Speed, Handling, Competitiveness in class, most fun to drive, prettiest paint job, ability to banter well with super-villans?
Its a pretty broad question, and deciding any car on a single criteria is an exercise in disappointment. The Escudo is obviously the fastest, the F1 cars obviously handle the best, and Everybody has their own car that is the most fun to drive.
I like the Opel Calibra Touring Car, but there is no way I would race it against an F1 car or a GT-One.