Interestingly, ARTNews occasionally publishes a list of the Top 200 Art Collectors in the world.
For example, the 2009 list can be found here.
Certain names are already household names, at least in the art world,, such as Stephen Cohen, the hedge fund manager, or Charles Saatchi.
Even though some names are perhaps less familiar, no one can deny the list represents the elite in the art world.