I've got a thermos "Backpacker Bottle" - I love, love it. I use it in the middle of winter on training rides. It keeps my tea hot for several hours even if it's in the teens, warm for longer. Zojirushi is making a version of this bottle now too - and as usual with them the design is way cool.

Thermos - http://www.amazon.com/gp/aw/d/B000RHDG7K

Zojirush - http://www.zojirushi.com/user/script..._category_id=5