In order to avoid the hassle with taxi drivers at the Madrid Airport, I had pre-booked the non exclusive shuttle service with Aerocity on GoMadrid.com. The web site stated 6 euro per person.
We ended up paying 40 euro for an adult and 2 children for a normal trip from the airport to the city centre.
If you only have 1 or 2 pieces of luggage, the best way to travel to/from the airport is by metro. Lines are clearly marked, the metro is well organised, vending machines are in English and maps are available at each stop. A ticket is 2 euro. Expect the metro to be more like Paris than like Shanghai or Hong Kong: longer walking times required to change through winding corridors.
Travelling through Spain often I sometimes use taxis. Never a problem in most places but it seems to be in Madrid. On more than one occasion I have wanted to go into the city but have been driven around it before going in from the airport. Normal price from the airport to the city should be between 12-16 Euros. Anymore and you're getting ripped off and taxis will do it. Not all of them but a great majority of them will.
Unique Suggestions: If you travel by cab ask for the price into the city before. If they say more than 16 Euros then they are going to rip you off and do not ride with them.
Fun Alternatives: Buses can be taken into the city but agreed, this is never much fun and can be a headache trying to locate one going in the right direction. Cabs are much easier.
I guess there's nothing wrong with paying 10 Euros to ride in a double decker bus and see the sights of Madrid, but I'd rather take advantage of the Metro and my own two feet. Instead of riding past the major sights in a fast moving bus, I'd prefer to walk! However, you can get on and off the bus and buy one or two day passes.
Unique Suggestions: For more info on Madrid Vision tours, go to: http://www.sleepinspain.com/mitgard/en/include/madridvision/madridvision.asp
Fun Alternatives: The Metro, a map and your own choices of sights to see!
I had read the taxi drivers might rip you off before I went to Spain,but I thought I had hired a cab with a friendly driver willing to tell me everything about his city....wrong....he conned me good.I gave him a large note for the fare..first mistake..the he shut the door for me..second mistake..then he took off at fast speed..laughing..I might add.always have small change for the transport especially for the taxi.