1. Volvo S60
2. Mercedes C-class
3. BMW 3-series
4. Audi A4
The S60 has a fantastic design, offers most space on the front seats, has a superior safety equipment and I really love the sound of these in-line-5-cylindre-engines.
The C-class is definitely a very good car with a nice exterior design but interior design is lousy. It's the worst one of these four cars.
BMW is a sporty car, but it is just much too small. Either you take the 4-cylindre-engine (118 hp) or you'll have to spend a lot of money - only to get the 6-cylindre-engine. That car is very expensive.
A few days ago, I sat in the new A4: nothing is really bad, but I just don't like that VW/Audi/Seat/Skoda style-mixture. I don't buy a car with the same buttons as I find them in a much cheaper car.
Exterior design of the A4 is quite boring.