I just installed Dragon NaturallySpeaking professional. It takes getting used to the speaking without making mistakes, but so far so good. The pros are that so far in this blog, what I have spoken is exactly what is being typed; and that after the minimal amount of training. Another high point was that I fed it a an MP3 recording that I made on a windy day and it came out 90% correct. The negatives are that even on my six core AMD machine the software lags in reactivity: I purchased professional version which allows me to hear my voice over the text that has been transcribed, and switching between correcting the text and listening to my voice takes a half second and that's too long. Still I'm very happy with the product.
This blog entry for example needed only four minor corrections from its original transcription.