Its pains me to say as an otherwise raging eco-activist...but I hate public transport at the moment. Don't know whether its privatization but it is TERRIBLE in the UK. Constantly late, services only once an hour, expensive, dirty, generally unreliable. Will be getting a car as soon as I pass.
It will obviously work out more expensive to run the car in the first year (due to high insurance, cost of buying the car), but after that (when you pay up to £2 a mile on a bus) its probably going to be about the same.
Plus I always say time is money, and so being able to avoid the hours wasted waiting at rainy bus stops and train stations will be invaluable. For this reason,it will mean reducing my commute from 2hr30mins to about 45mins a day.