Delft was the home town of Johannes Vermeer - a painter in the 17th century. He is justly fabled for his ability to capture natural lighting and colours. One of his paintings - Girl with a Pearl Earring - spawned a novel of the same title and subsequently a Hollywood movie.

http://www.vermeerdelft.nl/195.pp
http://en.wikipedia.org/wiki/Johannes_Vermeer


Rotterdam is home to the Rotterdam Philharmonic Orchestra. They're pretty good but a little less famous than their cousins at the Concertgebouw of Amsterdam.

http://www.rpho.nl/index.php?id=59


The Hague of course is the seat of many international organizations, particularly those to do with justice. Not sure what tours they have of the Peace Palace but I'm sure it's worth a visit.