Building a Music server

Hi All,

I am building a music server. My first one. So I need your experienced help in correcting my obvious and not so obvious mistakes.

I see a lot of advantages for using a computer as an input device to my receiver. Suddenly we are protected from format changes, Technology expiry etc.

My Design Objectives are:
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Store, CD Ripped and downloaded music with minimal losses.
Expandable Disk based storage with initial space of 120GB (I have a spare IDE)

Download and store music and video. So the machine should be connected.

A clean, small preferably touch pad screen for controlling the UI. Also a wireless control for the Keyboard and mouse.

CD Qualuity, Music output to my receiver.

Play CDs and DVDs (Music and Video to be channeled to my receiver.)

Fairly fast (Not for gaming). Tuned for good sound and video.

Sleek looking, so that it can fit into my music system.

Under $500

I am planning on an used P-IV machine with 512 MB RAM. Upgrade the sound and video cards. Add an USB card if required. Run a good flavor of Linux. An LCD screen (12").
An external sound processor of the likes of,

Stereo-Link 1200
Waveterminal U24
Edirol UA-1X
M-Audio Sonica
Yamaha DP-U50 CAVIT External Audio Soundboard

These are my initial thoughts. I am waiting for your comments. So please pen your thoughts.

Thanks
Boni