I think the possibilities for these are almost endless.
Small enough to do almost anything you want.
I think the main advantage is using them as client/secondary devices, but can be controlled/managed by a server/primary computer.
What springs to mind is media streaming as mentioned. plug it in & a simple menu system that can connect to a home server & stream from there, etc. XBMC Client maybe?
Everything good about the last 30 years of computing can be re-created. It would be easy for a teaching device having the teacher's PC/Laptop as a server & these as clients - dumb terminals/thin clients. Teachers could 'push' reading material, etc. to the clients & pull home work files, etc. for marking/grading... or maybe some sort of Citrix clone.
Maybe future versions could have audio in/out for simple VOIP, etc.
Others uses could be to make a cheap IP Camera or a cheap print server.
A front end like JoliOS would be nice - a nice easy user interface.
I think there's so many possibilities - they are even cheap enough for companies to give away as a marketing/promotional device... maybe giving access to a special area on a website or pricelists, etc.
Then there's VPN, etc.
Other future modules could accept sim cards for 3g internet, etc.
Its the kind of device where people wouldnt own 1, but 3 or 4 or 5 or 10, etc!!!
What I would really like to see, would be a collectors/special edition that is setup so you
can play the whole elite back catalog - it could even come boxed in a a re-issue of the original
Elite Packaging with the manual, etc. 'o)