I caught the premier of American Experience's John & Abigail Adams the other night and really enjoyed it, though the program's tagline ("Meet the original power couple") is discouraging. President Adams was a very interesting fellow, and I've been intrigued by him since I read Founding Brothers: The Revolutionary Generation by Joseph Ellis a few years ago.
An examination of Adams is especially timely now with so many issues arising with regard to executive power in the US. John Adams wrote the constitution for the Commonwealth of Massachusetts, which established three branches of government. It was largely the basis for the Federal Constitution when it was later drafted. He believed the separation of powers in government was critical to maintain democracy, and that left unchecked (esp. by the judiciary), the executive branch could move towards despotism.
I highly recommend watching the program if you've got two free hours. It's not just informative but also entertaining, and has catapulted John Adams to the top of my list of favorite founding fathers.