In general I suppose I look for aesthetics when I buy a new (s/h) car. Very rarely have I studied torques, or mpg's, or acceleration figures. For me it has to abide by certain design criteria, be an acceptable colour (not orange), and be reliable; the rest I leave to luck.
I remember my mother changing her car back in the late 1960's. I accompanied her to the Rover garage (they always bought British cars), and was amused to hear her ask the salesman for a car that would accelerate up hill.
She left with a Rover P6 3.5 litre V8 in dark metallic grey, which fulfilled all her requirements.
One old friend of mine (who I've known since we were about 5 years old) is a real petrol head. He always has several cars in his drive. Usually there are a couple of E Types, a fast runabout, and whatever muscle car that takes his fancy at the time. The last time I saw him it was a 4.5 litre TVR Cerbera; a beast of a car that he assured me was no less than a street legal Formula 1 car.
I have occasionally myself been tempted by sports cars, but have only ever owned one; a Triumph TR7 that was about as fast as a Renault 4. It was a very pretty car, but had no oomph; I eventually sold it to a man from my village who was leaving his wife. The deal was all very clandestine, and the car stayed in my drive until the time was right for him to steal away in the middle of the night, and head for Germany. It was all very 'cloak and dagger'.
My present car (The Compact Royce) is a 'break' version of a very classic French car. I shall keep her until she dies; hopefully well into the distant future. Not exactly 'keeping up with the Jones's', but frankly there are no Jones's here up with whom one would wish to keep.
How do you chose your cars?