@jakedduck1, I have become a water drinker - plain old ordinary water. I keep a 2 L pitcher on the kitchen counter and it is a constant reminder to me to have a drink. I can easily see my progress throughout the day. I sometimes make make unsweetened iced tea, and even enjoy using the flavored tea bags for variety. I have been known to make half-and-half (half lemonade and half water) My kids say "Yuck".
Water is my choice of beverage since my transplant, and I'm not exactly sure why I do that. I believe that other drinks count, but you have to be careful of the sugar content etc.
You say that you are limited to only milk and water. Is that doctor asdvised? Would you be able to add a twist of lemon or lime to 'jazz' it up? Would a straw help you to sip throughout the day? Or maybe multiple small glasses of water might be less intimidating than a large glass?
I'm getting thirsty! Gotta go take a drink!