Nice discovery on that Windows Speach - never tried it. Will have to plug in a mic and check it out.
I've used Dragon for years. There's a little bit of time needed on it's initial configuration to distinguish your voice etc, but I've used it for years when taking notes or phone call journals.
I never got into using it for browsing the web etc, but I know it can be done pretty easy. I use it for letters all the time. Heck, I SHOULD use it on these forums