The Mommy and I try to encourage LTD to drink water liberally throughout the day. The best delivery system we have found so far is from an unusual place. The Playtex Insulator cup with straw has been battle tested and has beaten all rivals. You see the little guy has an annoying habit of dropping his bottle from the highchair when he is done drinking from it. He truly pushes the concept of spill and leak proof to the limits. Because the Insulator can take a licking a keep on ticking we have a ton in the house and for the road. While they come with many design options, we use the ones with cars on them for water and dinosaurs for milk. Like most things these days they are BPA-free and dishwasher safe. In terms of getting the best bang for our buck the Insulator has come through for us as a true bargain. In fact I think the reason we have so many is that they are really inexpensive, sold almost everywhere and really easy to clean.