No one has spoken falsely in this thread
If all else fails, head to the capital city of the country you're in and find the US Embassy. You'll have to do that if you lose your passport anyway.
In fact, if you're not planning on driving, your driver's license will be pretty pointless, since they'll be asking for your passport as ID everywhere you go...
I strip out all non-essentials from my wallet before I head on a trip. Basically, I have some cash, a couple of credit cards, my ATM, frequent flyer cardd and my passport. Keys, non-essential cards (AAA and my dental insurance card do me no good overseas) all stay at home.
Although I have to say, the driver's license has been key as an icebreaker - it's always fun to compare ID photos with people @ the hostel bar!