Video Demo of Vista Speech Recognition
Chris Henley's blog has a must-see 15-min video of Windows Vista speech recognition in action. He did a very professional screen capture of a session that walks through SR on Vista, from how to set it up to how to browse the Internet using only voice commands.
This is a screen cast video, so you don't see Chris' face or an indication of the type of microphone he was using, but I can tell he had a good one because his accuracy was fine right out of the box. You can buy a good USB microphone for under $20 these days, so that shouldn't be a problem, but it's surprising how often I hear people say that our recognition sucks--only to find that they were using a bad microphone.