I don't like "travel mugs." They leak (my car console is evident to that) and they don't keep the liquids hot enough for me. I do like styrofoam to go cups though. While they do still leak, at least the coffee/tea stays hot. However, they're not so friendly to the environment, and as a family, we were going through about 12 - 14 a week.
So, a few weeks ago, I ran into a fellow Weight Watcher member at Dunkin Donuts before our meeting and she was getting a refill of her travel mug. I asked her what they charge her for that, it's 12 ounces, so apparently a small. Then I asked her if it keeps the coffee hot, and she said for a long time. Then, she proceeded to turn the cup over, and lo and behold, it didn't leak!
She got hers at Linen N' Things but I found mine at Bed, Bath and Beyond.
It was expensive, $20 but I had my $5 off $15 or more at Bed, Bath... so that worked out well - and I bought three. I figure, in what it will save on styrofoam to go cups, they'll be paid off in 20 weeks or so. And we all love them.
If you don't have a Bed, Bath and Beyond near your, or a Linens N Things, you can get it through Amazon.