Diamond color is graded from D, which is completely colorless, to Z which has more a visible yellow to brown body color. Although colorless diamonds are rarer and more expensive, the best color is truly in the eye of the beholder. Choose the color, or lack of color, you find most appealing and the best value.
Fancy color diamonds have a completely different color grading system and are rarer and often much more expensive. Fancy color can vary from distinct yellow to browns, pink, blue, and many other unique and rare one of a kind colors.