OK - this is probably out of scope for 'hardware' on a mostly roasting forum,but...
I pickup up a couple ~12oz double-walled glass mugs at World Market ~6months ago. They feel fragile, but aside from that they are nearly perfect. You see the beverage clearly, they hold heat extremely well, and they are reasonably attractive, very light weight.
All my ceramic mugs/cups lose so badly by comparison .... need to make their way to Goodwill.