I have lost none of my enthusiasm for this product as I have learned about it. And I'm not even a Windows guy! I think you will like this review at Ars Technica and find it easy to digest.
Whether or not it's a runaway best seller, my bet is that WHS will be a steady earner and increase it's sales as time goes on and more people feel the need for [both] secure backup and "one stop" organization of their files. (Whether multimedia, as Microsoft foresees, or otherwise.) This is the right product at the right time.