Best? That would have to be the Audi S6. Speed, looks, comfort, the works.

Worst? That honour goes to a 1985 Mitsubishi Colt. I've never felt so disconnected from the driving experience, especially the gearstick felt like it wasn't actually connected to anything... it's the only time I've taken the longer route because I didn't want to take the car onto the motorway. Of newer cars, the Kia Sorento deserves special credit.