Schiphol has six major car rental firms with desks conveniently located on Schiphol Plaza. Some rental companies also have offices near the centre of Amsterdam, too - maybe a better bet for a pick up if you're thinking of a driving tour of the Netherlands after a stay in the city. However, compare rates with those for airport pick ups, and bear in mind that you may be charged extra for picking up in the city and dropping off at the airport. See our money-saving guide on for how to get the best deals.
You don't want a car while in Amsterdam - parking is an expensive pain, the city centre is compact enough to get around on foot, and public transport is excellent anyway. Moreover, if you're planning on exploring the Netherlands beyond Amsterdam, travelling by rail may well be the best bet: appealing towns such as Haarlem, Leiden and Utrecht are easy day trips from Amsterdam by train.
That said, you might want a car to explore the countryside in the north or east of the Netherlands, or to get out to the beaches. The Netherlands' road network is excellent, with dual carriageways and motorways connecting major towns and cities - though do bear in mind that traffic jams are common on main routes.