Contigo kids cups!! We tried a ton of cups before we found Contigo. They don't leak!! There are different styles. My 2 year old uses the Striker cups. The spongy spout on it is durable! He chewed through many many dollars worth of straws on other cups. Our 4 year old uses Trekker cups. These are for a little older of kids because they have to wrap their hands around the cup to push a release button to drink. DS cannot use her cups yet and I don't think she was able to use them until after she turned 3.
I also like the contigos, I have used tehm for a few years for my coffee, they're amazing nad when I saw the kids' water bottles, I knew they'd be great as far as leaking, etc.
My kids like the Thermos Funtainers. They are stainless steel with a straw. If the lid is flipped open they can leak, but with the lid closed they do not.
Re: Recommend a water bottle
I also like the gerber stage 4 cup, they are leakproof. I found them at Walmart for $3. https://mobile.walmart.com/ip/Gerber-Graduates-Stage-4-Rim-Like-10-Oz-Cup/20512862