ok well what you need will be:
Sound Card (only if you really want one, most motherboards come with some type of sound output built into them),
Dvd Writer or just reader,
Operating system (windows, linix etc... ),
Floppy drive if you want,
Mouse and Keyboard.
I'm pretty sure thats all you'll need to build a running computer.
If I've let anything out somebody can currect me, but I'm sure I haven't left anything out.
Mother Board: MSI K8N Neo4 Platinum/SLI --- CPU: AMD Athlon 64 3200+
PSU: OCZ ModStream 520w ----------------- HD: Seagate Barracuda 200g
Video Card: XFX GeForce 6200 -------------- RAM: OCZ Value ram Dual Channel 256 x2