Marvel Classic Tumbler

I was skeptical about the flip lid truly being leakproof, but I tossed it in my bag with coffee and not a single drop escaped. The tumbler also fits perfectly in my car's cup holder, which is way more than I can say for most bottles I've owned.

The straw lid clicks on so securely that I tossed it in my bag without a second thought, and not a single drop leaked all day. Took it to a long meeting and my coffee stayed hot the whole two hours.

The double-wall insulation actually works—my coffee stayed hot through a full morning of errands, and the flip lid snapped shut without a single drop in my bag. The straw lid is a nice bonus for cold drinks, too.