The other thing to note is that if you are married even to a foreign spouse without green card you can file jointly and you now get a full $182,800 exclusion. There are also rules where you can deduct further for housing expenses as well as tax paid locally.
This is the IRS guide you should read. http://www.irs.gov/publications/p54/index.html
The bad news though is that for entrepreneurs, consultants etc. If you are self employed, in a partnership (including LLC's) you are not exempt from paying self employment tax (15.3% of the first $106,000 earned.
This is likely the biggest issue for some of the people renouncing citizenship.
The second issue also mentioned in the article is reporting of bank accounts containing more than $10k.
Final bad news for US entrepreneurs abroad is that your startup might be classified as a Controlled Foreign Corporation, which in theory could lead to it being taxed in the US. These rules are so complex they make my head hurt just thinking of them. This PDF seems to explain it fairly well:
And you have to pay the US first, meaning the country where you stay is gipped, even while providing THEY provide you with social services.
Which the US, of course, doesn't.
Trust me, I don't misremember - it made me mad as hell.
Your expert disagrees with what mine told me, and it seems to disagree with the IRS as well. I'd suggest you obtain a second opinion if this situation is relevant to your life.
While the rules aren't great, they're not impossible either.