Best and maybe not as expensive as you think, several counters are located right outside the baggage claims. They might appear a bit pushy and look like touts, but they are not. It's just competition: if they don't convince you, the next counter will (or might). It cost a bit more than taxi meter, but it's hassle free (well most of the time) and prices are clearly displayed (expect 400 to 600 Baht but you get a nice new Camry.)