As others have pointed out before, Darth Vader's helmet has a very Samurai-ish feel to it. For example, the venerable Star Wars website had a complete article on it a few years back.
Check out this article on Darth about the man behind the mask which also has a letter printed by fellow Empire blogger, John Rozum. Here's a peek at a more David Prowse-ian head behind this spinning head thingamajig.
Let's match his helmet with some actual Samurai throughout Japanese history. Hmmm. Let's see, I have a couple of Kurosawa's 7 Samurai, but they're not even wearing helmets.
Oh darn, neither are these half a dirty dozen.
Nor is this guy...
Okay, we're getting closer...
Let's doublecheck a few of the Darth pillows I own. Nope, not quite.
Well what do ya know. Sendai's own
伊達 政宗 (Date Masamune) has a similar headpiece, if you take off the banana, substitute a masked inhaler for an eyepatch and we may have ourselves a winner!