I love love love the Nissan Leak-Proof BackPack Bottle to keep my coffee HOT. I never thought of it to keep water from freezing, but it sure would work. It even has the ridge for the water bottle holder and I find it works great on a bike. (interesting, since that isn't its intended purpose). It has a really great flip top lid that makes drinking on the bike, then resealing easy.
Can get it from Sweet Marias, I'm sure from other places as well.
http://www.sweetmarias.com/prod.trav...-bottles.shtml
not cheap, but truly works for coffee anyway.
I gave one to a friend for Christmas last year. Her complaint is that it keeps her coffee too hot.