What does Mr Darcy look like?

In the book, Austen gives very limited physical descriptions of her characters, including Darcy. One of the very few things she makes clear is that he is tall. The first--and really, only--description she gives of him is from Chapter 3, and merely says that he is tall, handsome, and has a noble air about him.

He has been portrayed in movies by Sir Laurence Olivier, Colin Firth, and Matthew Macfadyen, as well as others in knock-offs and retellings. All three of these men are dark-haired.