Pulblic trasport in my area sucks. In the city it seems cheap enough. For me to get to and from the city it costs £4.80 on the bus and it can take up to an hour depending which bizzare route it takes!
It's an 8 mile drive so can be in town in 20 mins easily. Parking for £2.30 in a multi storey for 2 hours and lets face it, I'm a bloke. 2 hours is more than long enough!
Ok, tyres and wear and tear aside, I think it's cheaper taking the car!