Save your money and buy an Antigravity insulated mug:

http://www.antigravitygear.com/proddetail.php?prod=AGCZZPMG

Lighter, cheaper to buy (and replace), better insulated....did i say lighter?

If you do go with titanium, get a single wall so you can cook in it. That makes it multi-purpose. Single wall titanium will burn your lips, but will also cool quicker. Make a cozy yourself out of Reflectix and it is just as good or better insulated than a double wall (lighter, too). This is a light-weight forum,remember, guys ?

BF