3. Samurai -- Darth Vader is obviously based on samurai armor. The jedi are the same as the samurai even down to the names (obi-wen kenobi and qui gon). It's also a reference to the Ronin, masterless samurai.
There are many who believe that Darth Vader is based on the villain The Lightning from the 1938 serial The Fighting Devil Dogs. Star Wars itself is obviously an homage to those old serials so it would make sense for Lucas to draw inspiration from them for his characters.
Apparently Darth Vader is 'Dark Father' in Dutch (the truth was there from minute one) so perhaps Lucas stole the X-Wing design from all those windmills in Holland?