Toby, I am far from an expert but I have researched this for my restoration project.
To get a "show car look" and a ripple free effect, most of the work goes into the body. My car was stripped to the metal, dings removed (by pulling the metal, and then a thin thin coat of liquid metal or filler). The car is then primed with epoxy primer, wet sanded, repeatedly primed (as many as 6 times). Each time between the priming-sandng cycle, a "shadow coat" of black or dark primer was sprayed and then wet sanded off. Any high or low spots show up and can be addressed individually. Different gauges of sand paper are used, going from more to less coarse as each prime-wet sand cycle is completed
This repeated priming and sanding is what gets the body smooth and even and ready for paint.
Then comes the paint. As I understand the process, there is just one spraying session for the final color coat of paint, but the person applying paint will go over the body enough times to ensure a complete coverage and it goes on heavy with the new low volume high cover paints and paint guns. Less solvents to evaporate, as they tell me and more environmentally friendly.
If you use paint/clear coat, then the clear coat goes on. What gives the deep shine of a show quality paint is that the clear coat is wet sanded to eliminate the "orange peel" which is is essentially a series of ripples in the clear coat that can form after the coat dries. Orange peel gives the car a dull look and virtually all factory painted cars have this-even my 1999 e320 wagon. Reason is that it is a expensive step to go back and wet sand.
I am sure there is some inaccuracy in one of the details I shared, but essentially, your perfect paint job is not in the number of coats of final paint, but the number of coats of primer and the individual wet sanding and body work done at each step of the sanding and body finishing work.
If you have a newer car, you would not need to go back to the metal, but would want to have several steps of wet sanding to ensure you get the body back to smooth and the dings fixed. Cost without removing all of the chrome would be in the $2-4,000 range (US dollars). I had to go back to the metal as the car is 30 years old and had a number of paint jobs and several rust spots. I needed to get it back to metal to make sure there were no hidden rust issues.
Here is a reference for Q&A on Body Work. Good luck!
http://www.autorestorer.com/q_boards/body/index.cgi