As a U.S. citizen you are required to pay taxes on income earned worldwide and from my understanding you can only deduct up to ~95k in 2012.
From what I've read, being a US citizen and working abroad is expensive and one of the main motivations for people to renounce their US citizenship.
So if you live in a higher tax jurisdiction (i.e. the majority of the countries in the world), your US tax bill ends up being $0. However, you still have the hassle of filing your US tax return each year.
i.e. Mutual fund account - $32K