I stumbled across a new app on the net that uses the cool new recognition platform and recognizer included in Windows Vista. It's called Dee Jay and it was written by Martin L. Shoemaker from Inkon Software. I haven't downloaded it myself, but from it's description it sounds very cool.
Here's what Martin says you can do with it:
Here is a list of the Dee Jay commands. Note that you can change Dee Jay's name, so replace "Dee Jay" with your chosen name in these commands.