H.B.
I had the same situation with my kids, and they would only drink water from a cup at that age - no interest in bottles or formula. I'm not into giving my kids juice, it's really just sugar water without much (or any) nutrition. Sugary drinks are a huge contributer to teen and adult obesity, so I figure if I can avoid them starting that habit, and help them learn to enjoy a refreshing glass of cold water on it's own, so much the better! So, at my ped's ok, I let them become water drinkers, and mixed as much formula and breast milk into their food as I could. So a portion of pureed meat, fruit or vegetable would be mixed with 2 scoops of formula, rice cereal and water or breastmilk. They ate it up. I also started adding in other things like flaxseed oil, avocado, and wheat germ to get the healthy fats and omega-3s into their diet. At age one, when they started eating more finger and table foods, we also added cow's milk, so I stopped using the formula. I sometimes still drizzled their veggies with olive oil to get some extra fat in them, though.
My kids, at 3 and 1 1/2, are great healthy eaters, they both still love to drink water and prefer it over almost anything else. Instead of filling up on juice or bottles of milk like some kids their age, they eat well at mealtime and snack times - whole grain bread, cheese, meats, vegetables, whole fruits, almost everything we eat. They also drink a cup or so of whole milk a day, and some orange juice, since it has vitamin c and good citrus can be hard to come by around here. They're always well hydrated, and I never have to tote around cups of juice like other moms, they just take sips from my water bottle, or have their own in the car.
Hope that helps!