The airport charge has been the same since it opened over a year ago. It does include the 50 baht airport tax and the toll fees - I think 105 baht. I think it was about the same as the price from Dom Muang airport so there was a price hike but not as high a percentage as the rise in fuel costs.
Fuel costs vary but a taxi on LPG the return journey costs about 350 baht and gasoline about 700 baht.
Most taxi drivers rent their vehicles for 1000 baht for 12 hours.
Meter taxis will often get a return fare. There seem to be scouts on motorbikes on Suckhumvit Road Pattaya who drive alongside any meter taxi arriving and offer them a cheapo fee return fare. As they have to go back anyway the driver is keen to get anything he can.
For POSH friends
http://www.imagelimo.com/ are the place to go.
My experience of meter taxis is variable but I have had some semi-suicidal ones and some less than reliable cars. Don't even ask about insurance cover. Once you are on the motorway you can't change.
I now prefer to use drivers that I know are careful and vehicles that are comfortable and reliable. It costs a little more but I am worth it!! I pay 1300 or 1400 for a car from Pattaya to Bangkok.