This is not the dash of the comfortline model - its much nicer with a wood trim. Difficult to argue that the Saab is not a good/nice car - it is, I agree. But you will get a fresher Passat and it will hold it's value better (no doubts there). Plus, a passat will sell quicker, more demand as the Saab is a hight class car. A fresh A4 is also a nice buy - very solid reliable car and very good resale values.
I agree with smcgiff - a car is more than just a method of getting from A to B. Some people enjoy cars, spend alot of time in them and appreciate them. I'm one of these. Fair enough it will deterieorate, but it's more a question of spending your money on what's important to you.
Whackin - on the cooper - I'd stretch for the Cooper S - a mini with a super charger - wow! Incredible resale values on these also, but not practical for me with space :-(.
When all is said and done, you need to decide yourself. Get advice, sure, but go with a car you like and that makes sense for your lifestyle, and that you will enjoy!
Anyways, hope that helps.