Personally, I would start with code.org or Scratch. If you have an ipad, there is Hopscotch. Here is a huge list of more tools to teach young kids programming: http://bit.ly/ortonacode
But if you start with basic or python, you'll be teaching them that coding is basically similar to solving boring puzzles - not of any real use, and not as fun as videogames.
Start instead with something they would find motivating or useful, not you. Making a game, or creating a useful little app/tool that solves some problem they think is important, etc.