I'm trying to get into the habit of drinking more water throughout the day. The Camelbak Eddy Bottle is a great way to do it, because:

1. It doesn't spill when knocked over (you have to bite the valve a little for water to flow).
2. It has a straw so I can idly sip without having to tip the bottle.
3. The loop-cap makes it easy to carry around.
4. It doesn't impart a metallic taste the way a Contigo tumbler sometimes does (which is why I reserve the Contigo for drinking coffee on-the-go instead).
5. The whole thing is dishwasher safe.

$15 on Amazon. Available in seven colors.