I've been here 3 1/2 years and am just getting around to taking my lessons now. Up to this point, we haven't needed a car. We've lived in areas with excellent public transport and work in the city centre, etc.
We still don't need a car, but we want one for the sake of convenience -- going to pick up big stuff, running down to the shops quickly, getting to the doctor or vet in 10 minutes rather than 30, etc.
The sticking point for me is children -- if we have kids, we MUST have a car. I absolutely refuse to drag children (and all of their paraphernalia!) onto a bus or metro!