What makes skin soft without causing it to be greasy?

Milk? I have read that milk baths soften skin, though i don't know of any scientific evidence that it's true. A good emollient lotion (aveeno, eucerin, neutrogena, many others), applied regularly, will help. No matter what you've heard or read, drinking gallons of water will not soften your skin or prevent dryness or wrinkles.