It has come to my attention though much nerdy discussion that when one wields a blue lightsaber blade he is doomed to failure. Only a green blade will get the job done, and even that doesn't guarantee you'll walk away without a scratch.

TPM: Maul (red) kills Qui-Gon (green) and defeats Obi-Wan (blue), but Obi-Wan kill's Maul with Qui-Gon's saber.
AotC: Dooku (red) defeats Obi-Wan (blue), but Anakin (green) hold his own until Dooku chops it away leaving him only with Obi-Wan's and quickly defeated. Yoda (green) fights Dooku to a draw.
ANH: Vader (red) kills Obi-Wan (blue).
ESB: Vader (red) defeats Luke (blue).
RotJ: Luke (green) defeats Vader (red). It is only when Lukes tosses away his blade that he is harmed by Palpatine.

I'm sure RotS will shatter all this (throwing Mace's purple saber into the mix, and we all know how Obi-Wan and Anakin's the blue vs. blue duel turns out), but it's an interesting point nonetheless.