Having used Dragon and other speech-to-type software in the past, this post by Xavier at MIDStories caught my interest and impressed me. You have to watch this video if you have ever used speech-to-type software. I will have to give Dragon Naturally Speaking another try at Nuance.com.
Since I use a Tablet PC, I did a search and found a few interesting reviews, most on earlier versions. Here are a few:
From MedicalTabletPC.com, gizmag.com (today and pretty funny), and GottaBeMobile.com.