Colorless diamonds are the most desirable since they allow the most refraction of light (sparkle).
Off white diamonds absorb light, inhibiting brilliance.
Diamonds graded D through F are naturally the most valuable and desirable because of their rarity. Such diamonds are a treat for the eyes of anyone.
But you can still obtain very attractive diamonds that are graded slightly less than colorless. And diamonds graded G through I show virtually no color that is visible to the untrained eye.