The 'must-have' design tool

Jon Rowett has blogged about LEGO Digital Designer which looks really cool, especially if you ever played with LEGO (just about everyone) or read Douglas Coupland's Microserfs. As I have a two year old son, who is at an age where I can begin to introduce him to the delights of building stuff with plastic bricks, I will have to download LEGO Digital Designer immediately and evaluate it's usefulness as a design tool. Thankfully, there's a version for MacOSX as well as Windows.