I prefer distilled water. It has the ability to remove toxins from the body and other inorganic substances from the body as well. Some will say that distilled water will take the minerals from the body and will use urine analysis to prove their point. But the body will only let go of inorganic minerals. Water with vitamins or minerals add is not even water any more once you add something to water that is inorganic you have a crude chemical mix that in not fit to drink.
Spring water would be my next choice, then filtered water. What ever type of water you chose just be sure of the source.