Wayne,
I've got lots of friends who have used Scratch with their children, and they loved it as a start. When their kids wanted to be able to do more than the block-style languages allowed, that's when they made the switch to Python or JavaScript.
I chose to use Python from the start with my children (starting at 2 and 4, now 5 and 7) - they would sit in my lap and come up with fun changes to the short programs I'd write, I'd help them find the keys to type in a change or two, then we'd watch the result.
I believe Python's turtle graphics offer as visually rich an experience as Scratch or Blockly, and kids love seeing the results immediately.
Plus, I love a good-old-fashioned text-based adventure, like the MadLibs app we build at the end of chapter 1
.
I think the important thing is finding something your kids enjoy, whichever path you take, and spending time with them at the computer, together.
Best wishes, and happy coding!
Bryson