Just spent spent some time talking to Pogoplug, a company that makes a home-based media server. Don't switch off: there is a business angle to this.
This small, but very pink Linux-based device publishes multimedia data both inside and outside the premises, routing via an external server for Internet access so as to avoid creating more security holes that could result were you to allow home users to configure things.
And if you've got two Pogoplugs, they can talk to each other and set up a private cloud between locations. Imagine how useful that could be in situations where like companies cluster: only one need provide and host multimedia data, but others could add to the data store. Even if you have only one (and they're cheap, so why not two?), others can log into it, given the correct permissions and authentication.
The only downsides I can see are that the data must be hosted on a USB drive - though I'm sure that could be circumvented - and that security is, as befits a residential device, only as strong as your passwords.
And the big upside is that you get the advantages of cloud computing: data accessible from everywhere but without either the pain of a monthly charge, or of having to upload gigabytes of data at slow ADSL upload speeds to a remote location.
What happens if the company goes bust? They promise to make the secret sauce open source, so permitting further development. More on this as it unfolds - if anyone's interested...