Surely a nice cluster or perhaps a server farm even!

People may need raided a mirrored drive on their PC, and
a form of shaddow copying for backup... But a server?
How many films can you want to rip and store?

Oh yes, he's to sell Longhorn server to someone!

What nonesense!

"How many films can you want to rip and store?"
...Well, Not everyone is like you, you know! :)... I personally have 600 CDs and 300 DVDs, all RIPed with loss less quality, that's a start for you. around 3TB space in RAID-5. Instead of having my walls full of ugly CD and DVD cases, all in a nice little box, outside my room, zero sound, zero hassle. all in one place.

I find it likely there will be several things missing from this concept that would break it for me.

Currently (from what I've read, it seems there's a lot of speculation, but the best info I've seen comes from Paul Thurrott) seems to indicate that WHS is built on Win2k3 Server R2.  No problem so far.  I do wonder how you'll be able to network boxes running Vista Home Basic/Premium to this.  My guess is only through shares, since they don't have domain support.  Because of this, my additional concern is that WHS won't have options for domain support either, so having Vista Ultimate wouldn't matter much for networking.

Assuming WHS is based on R2, there will be no Bitlocker support for drives on your WHS box.  Due to limitations on versions of Vista, I'm also guessing the box will lack Remote Desktop support, or support for basic web/FTP stuff if I wanted it.  I also want to know if the WHS box will support three drives in RAID-5 (software at least) for redundancy's sake.  But I guess we'll have to wait and see what we're truly getting when the product comes out.

I guess I'm asking for a home-user product that will fit enthusiast needs, so I'm probably asking too much.  In my case, I'll probably need to resort to a full server OS, or a NAS-box based on a simple, but proprietary UNIX (i.e., Buffalo Terastation, Infrant ReadyNAS). 
All the complexity also makes me wish Microsoft wasn't diversifying Windows into so many different versions; it may make them money, but it's confusing and complicated for those purchasing their product.

I forgot to mention, I wondered whether document redirection could be made to work.  I'm not expecting full Group Policy support on a home product, but the simplest way for a home user to have their files backed up would be through folder redirection to the server.  Hopefully they have an easy way of setting this up.

In the world of today with homes getting more and more Desktops and Laptops this is a good idea target market would probably be Windows XP Pro & Windows Vista Business/Ultimate Owners.

With it being built on 2k3 R2 (posted in previous comment) we can hope that they take more ideas from the SBS 2003 and strip out components like Exchange and Share Point and a ton of other features that home user would never need, But keep in a basic configuration for things like Home Folder Redirection, and the connect computer.

  Windows XP Home/MCE and Windows Vista Home (premium) may not support GPO editing or joining an AD. However most (if not all GPO's) just make changes to the registry so with this said Computer/User Management would be possibly.

Like I said the idea has merit how, Think of how often you or firends liek to share files with in your personal networks...But we'll have to wait and see how they do it guess...