Best voice recognition software out there?

[Xcellere]

Hey gents, I'm wondering what would be the best voice recognition software for my father to use. He'll be using it to write emails in Outlook, Word documents, Excel spreadsheets, things of that nature.

 

[Schadenfroh]

Dragon Naturally Speaking

 

[Xcellere]

Any other opinions?

 

[Sforsyth]

I have both IBM and Dragons and I like Dragons better, I think it's verion 8 or 9