I've bough Chevs, a Ford and then an other Ford, and the sales process in all of them left me with a slimy feeling and an ache in my posterior.
I'd have to say that my best car sales experience so far has been when I bough my MINI Cooper S. Absolutely no pressure sale, (really, the car is its own salesman) and no hidden rip-off fees. Even when it was time to pick up, and the finance guy asked if I was interested in any protection packages, I politely declined, and the subject was never brought up again. But they aren't excactly budget type cars neither.