To all the people who said "I want X color because it means Y", you are tools. None of the colors mean anything. It's just a freakin' color. And I can give exceptions to every rule I've seen.
-Blue is a good guy's saber. Hm, a quite influential Sith Lord used a blue one, by the name of Exar Kun.
-Green is used by contemplative people who study the Force more. Cin Drallig used a green saber (canonically, I know there are pictures of him with a Blue), and he was the Swordmaster of the Order.
-Red is for Sith lol1!11!!1 Really? Leia was an instrumental Jedi following the movies, and she used a Red saber.
-Black would be a great stealth weapon/good for Sith. Yeah, it would be, if it was at all possible.
-Silver is used by people who believe in balance. Uh, no. The only canonical Silver/White sabers I can recall are used by Imperial Knights, who are simply bodyguards.
-Purple is for the strongest fighting style (Juyo). Maul used Juyo. Red. Kavar used Juyo. Blue. Zez Kai Ell didn't use Juyo, purple.
I pick Red, because I think it looks the best. It's an aggressive color, and is the most intimidating.