I have a TV and a (separates) hi-fi system in my living room, and my family members have laptops and desktops and so on. All the computers are wirelessly networked, but my question is what sort of device I would need to attach to my hi-fi and TV in order to play media from all pcs in the house, and where I can obtain said items cheaply in the UK. Wirelessly networked devices would be ideal.
To my knowledge the easiest way of getting media on a computer to play on a TV is through a decent graphics card, one with a DVI or S-Video output (depending on whether you have a digital or an analog TV). This basically means that you'd need a PC connected to your TV all the time, but also networked - you could then use this PC to access the others in the house and play any of their media on the TV.
As for the hi-fi system, likewise you'd need a PC. Probably a simple 3.5mm stereo jack (if you're using stereo, that is, or more if you've got surround-sound and your PC has a 5.1/6.1/7.1 sound card) connected from the line out of your PC sound card to the line in (if it exists) on your hi-fi sound system would resolve the problem. If your hi-fi system doesn't have a line in.... then some rewiring and soldering would probably be required (which I doubt you'd like to do to your hi-fi system).
Basically, you're using the TV and hi-fi system as the computer's screen and speakers. This is the easiest and cheapest way I can think of (as long as you're prepared to connect up a laptop or desktop computer to do this whenever it's required).
Assuming you don't have the required tools/equipment necessary to do this, then what you need is a decent graphics card (sorry, I don't know how much they cost in the UK); a decent sound-card (number of channels depends on what your hi-fi system is); S-Video or DVI cable; one or more cables with the appropriate plugs on the end for connecting the sound card to hi-fi system (or the TV audio input, which would need a 3.5mm stereo jack at one end and probably two RCA plugs at the other, if it's analog). These should be easily obtained from your local computer and/or electronics stores.
There are probably other devices that you could use to do this, but I'm not familiar with them.... so I hope I've been of help.
Is there a decent dedicated media PC available in the UK for a reasonable amount of money?