Alice in Wonderland - Lewis Carroll's imaginative trip down the rabbit hole and through the looking glass has endless possibilities.
Dorothy of Oz - There's a reason so many different versions of L. Frank Baum's creation have been made and continue to be made. It's loaded with potential for new stories and in the right hands it might work. Look no further than Wicked for a prime example.
Dracula - The greatest vampire of all has been interpreted and reinterpreted countless times. Why not take a stab at him yourself?
Dr. Jekyll and Mr. Hyde - A man with two personalities, one good, one dangerous and out of control, has inspired many similar characters throughout the decades, including the Hulk.
Ebenezer Scrooge - A Christmas Carol is one of the greatest stories ever told. It never grows old.
Frankenstein - The mad scientist and his undead monster were arguably the first science fiction characters ever imagined. They continue to endure.
The Gods of Olympus - Mythology is rich with incredible characters and fantastic stories.
King Arthur - Maybe Arthur and his Knights of the Round Table were based on real legends, but whatever the case the adventures in Camelot have become a great source for more fictional tales.
The Musketeers - Swashbuckling fun for everyone!
Red Riding Hood - Name a fairytale and it has huge potential to be reimagined.
Robin Hood - Stealing from the rich and giving to the poor is still a great theme today.
Sherlock Holmes - The world's greatest literary detective continues to be rewritten for each new generation.
Snow White - Disney may have given them more fame, but the storybook characters of Snow White and all the rest are still in the public domain (but be careful, Disney's own interpretation of those characters is still the intellectual property of the Mouse House.)
Tarzan - In today's over-connected technologically advanced society, what better metaphor than an Ape Man living in the jungles with the animals.
Tom Sawyer and Huckleberry Finn - Mart Twain's greatest characters still inspire audiences young and old alike.
The Wolf Man - Werewolves are a dime a dozen. None managed to spark the public's interest as much as this Universal Pictures invention.
Zorro - More swordplay from a masked avenger!
Okay, let it rip -- which great public domain character have I left out but still holds a place in your life.