Red double lightsaber is my standby in both games when I'm playing dark side.
Violet or silver is another favorite. Double bladed, of course. My ds Exile tends to favor the silver double blade.
Then in my last play through I discovered the Mantle of the Force, and my light side Revan favors that.
But there is a black lightsaber that my ds Revan may prefer, one that I had taken from a mod and customized.
I'm also working on a multi-color blade. For the game.
Myself, I would go with a double bladed saber with red, black, silver, or violet blade. The violet would favor more of a blue, not the pink in the game.