The image of Lugosi's Dracula is heavily copyrighted; Nosferatu is, by contrast, an open source vampire; you could tell that from his cameo a few years back on Sponge Bob Square Pants. The silent classic was originally a bootleg version of Bram Stoker's novel. When Werner Herzog went to work on a remake of F. W. Murnau's 1922 vampire film, he could call his creature Count Dracula, thanks to public domain laws. Herzog preserved much of the original's style out of admiration for Murnau and "the most important film ever made in Germany" (maybe so...any other suggestions?).
But Herzog's skeptical, neo-documentary approach--seen this summer in Rescue Dawn--wouldn't permit him to use Murnau's mistier plotting. He took pains to see how Nosferatu works. Why has no one burned the evil castle down in daylight? Simple: it doesn't really exist except in ruins, "except in the minds of men" who are tricked by the darkness of night. How does the vampire beat Harker home? There's a line about how the sea voyage is faster than heading back from Transylvania overland. (Unlike the book, this is set about the time Murnau set his version, 1838; there are no railroads yet in Central Europe.)