The medieval centre of Delft is a great destination to explore in your rental car, with its intriguing old streets, canals, and wonderful architecture. It was also the home of the painter Johannes Vermeer and the 'View of Delft' is one of his most famous paintings. You can also explore the city's Delftware, which is distinctive and famous local pottery.
The Hague is a little like a seaside resort in some respects but it is also the location of international courts and the seat of the Dutch government. There is a thriving expat community in The Hague and a real party atmosphere in some areas. However, the city does have a serious business side and is definitely place where visitors can enjoy a unique atmosphere, combining business with pleasure.
A drive out to Kinderdijk will reveal a charming place that is a must-see when in Holland. When you arrive, you will see its 19 historical windmills dating back to 1740. Since 1997, these have been part of a UNESCO World Heritage site and are an incredible landmark on the Dutch landscape.