What about starting with DIY?
I'm thinking Trustix Secure Linux - Home
paired with Webmin
Samaba, Apache, DHCPD and many more are included in trustix. Last time I looked, webmin was not but was an easy install. That could be set up on a Pentium I box because trustix is intentionally light weight -- nothing there that isn't needed for a server. I'm not so sure about the state of video streaming, but audio is certainly ready now.
That combination would give you files in native windows speak (CIFS). Apache would give you http, webmin would allow you to distance yourself from the CLI and allow administration via your (familiar) browser.
Why spend so much $$$$?