PT: Mace Windu. Purple lightsaber, force crushing Grievous as he "escapes" with palpatine for the kiddnapping, nearly killing Palpatine. Certified BMF
OT: Boba Fett, figured this would get more play. One of the most popular characters inspite him having one line and a cheesy death.
Video Games: Revan, hard to beat a guy who can do everything!(ignoring the book). Plus his story threw me for a loop and I remember playing and being all OH SNAP!!
EU: And I can't believe this hasn't come up but, Darth Bane! Inventor of the Rule of Two and the reason the sith ended up being so powerful in the end. Plus he makes an apperance in Legacy to mock Darth Krayt...and that is ok with me