Media Sharing Alternatives & Solutions

The biggest new thing to media heads (which Mac users have been enjoying as a standard for a while) is the ability to stream songs/videos or control playlists and libraries over a localized network. I've been waiting for this and I've been reluctant to buy alternatives like wireless speakers and whatnot because I think all the essential elements are in place and theres no need to spend any money on equipment I already have.
This scenario is very typical: you're sitting at home, in your flat or in your room, you got 3-4 friends over and all, or almost all of them, have got some sort of computer beneath their fingertips.
They have music, videos, pictures, even programs they want to exhibit for some reason.
I don't know about you, but I'm sick of playing DJ to the wim of everyone i have visiting, because my playlist is never enough. So, i want them to do it them selves without us having to change places on a frequent basis. So, I see a few solutions:

1. Using Windows 7's built in Media Sharing, which allows you to either stream media or play songs directly on a remote computer, and it is compatible with Windows Media Player and even Foobar2000 (Beta)
2. You can use VLC to stream videos and music, and you can also use playlists
3. Foobar2000's UPNP component, which allows you to stream music from one computer to another, or control whats playing on the other computer
4. Foobar2000's HTTPD component, which allows you to control the playlist via a HTTPD interface
5. Use Windows Network to play files from one computer to another

BUT...

None of these solutions are what I want. Consider Flash music videos, Spotify, Grooveshark, and a ton of other media distribution applications that still makes me have to play DJ. This will not do.
So I'm looking for something a little special, not sure if it even exists, but a network driver that allows sound output from the Windows mixer to be streamed from one computer to another, or to a "server".

This way I people could play whatever they wanted without me having to switch between my work laptop and my crappy stationary "media center".

Sorry for the long post :P
and thanks for your thoughts ^^