Hitler would probably have remained a struggling artist, and Mussolini might have stuck with socialist.  Their huge egos would more than likely have stayed huge, but they might have had little to no audience.  A New York Press article, written on April 4, 2002, titled If Germany had won WWI, makes these observations:

• Six million jews would not have disappeared.
• The dynasties would have survived, which means there would have been no communism with its 20 to 100 million victims.
• The ottoman Empire would have lumbered along.
• Iraq would not have been created.
• Israel would not exist, no Lebanon or Jordon.
• Russia would have joined the modern world, eventually.
• There never would have been a Vietnam war.
• The Kaiser was a civilized man, as were the Germans, and had the Allies humored him and allowed Germany to pursue her destiny, we would today be living in a far, far better place.

Of course, these are all speculations.  No one really knows what would have happened had Germany won WWI.  The world can be a scary place.