Titian, Botticelli, Vermeer,
etc.etc.etc. they're all great - but Picasso is in a world by himself, like Einstein. See his line drawings (e.g. of Stravinsky, or [link|http://www.picasso.fr/Pablo/genealogie/olga1.jpg|Olga Kokhlova]), his sculpture, his rugs, etc. etc. He has to be the world's foremost visual genius. Something about his dissection of things is infinitely fascinating - a series of drawings of bulls comes to mind - he starts with a full, snarling bull and abstracts it gradually into a stick figure - amazing.
-drl