I've got a media device.
it's made by a company called Emprex, and is called an ME1, I got mine off ebay for £50.
in it's normal setup it just plugs into a TV, and lets you play movies from either it's local hard drive, an attached USB hard drive, or a remote location such as from a PCs shared folder. or record TV to it's local hard drive. and with that recording comes the ability to pause live TV.
but it runs linux as an OS, which means as a geek it's really like my duty to mess about with it and make it do more.
I've now got it setup so that it's go a web server so that I have external access to the content that's on the box,
I've got it setup with samba (as internally it runs linux) so I can share documents and copy stuff to it whilst I'm at home.
I've also got gmedia server and mediatomb running on it, (still trying to make a descision as to which is best).
Also, when the box is recording TV, if I use a capable media player (like mplayer) I'm able to stream near TV to my laptop, when I had a windows mobile phone I could stream TV to that too. (there's no player for the file type on iphone
)
as far as efficiency goes, it's pretty brilliant. it's got something like a 9watt power supply, I guess I have to factor in the USB disk that hangs off the back, which probably adds about another 5 - 10 watts... (inside it's got a 200MHz MIPS processor, and a dedicated graphics chip for makeing HD video (only 720p though
)
I've got a few hundred GB disk sat inside the device and a 1.5 TB disk hanging off the back. I could ut a hub in there and connect other devices too.
don't get me wrong, a PC is great, and a PC will do more, but a PC will be noisier, cost more to opperate due to a larger power draw, and be more expensive to start with. (I paid less for the media server device than I paid for the external hard drive).
or to put it another way, £50 is about as much as you'd expect to spend on a nothing too special case that comes with a power supply.