Major Car Rental Services

There are few car rental services which provide cars to rent all over the world. Some of them have names which can be easily misunderstood for promotional slogans like: Budget car rental, Dollar car rental and Enterprise car rental others have more "suitable" names like Alamo car rental, Hertz car rental, Avis car rental, Thrifty car rental, Sixt car rental, ...
Which one is the best is up to you, but you can still choose one of probably cheaper local car rental services if you are lucky and find one.