The airport taxis run by Zona Taxis run on a fixed fare basis, so there's no opportunity for being ripped off. About 4000 HUF to the centre and cheaper return. Much quicker than the minibuses and cheaper for 2+ people.

The airport minibus service is good for single travellers. If you are travelling in a party of two or more, take the Zona taxi service from outside the terminal. No rip-off is possible, as the service charges a fixed price. The prices are clearly displayed. It's even cheaper on the return journey. Some Budapest taxis are dodgy, but the Zona service is not. City Taxi (211 1111 within Budapest) are also reliable and have English-speaking operators. No vested interest here, just a UK ex-pat who spent eight years there.

Just get the train! Can be found opposite the airport, takes you to Nuygati and cost HUF320. Quicker and cheaper!