Thermos Nissan Bottle ($22, Amazon 4.5 stars, 340 reviews)
Keeps hot drinks hot and cold drinks cold, has a few different sizes, can be operated with one hand, extremely easy to clean. I left coffee in it for over an hour and it was still too hot to drink. Can be tossed in a backpack or briefcase on the go.
I purchased the linked size and like it a bit more than any other thermos I've used. Thanks.
I have often benefited from recommendations for Things I Didn't Know I Wanted.
Given that Less Wrong is a community of unusually intelligent, critical, and self-improvement-focused people, I suspect we can generate a pretty helpful thread of product recommendations — perhaps even a monthly thread of product recommendations.
Rules: