I am planning on buying a Mac Mini to use as a music/media server. I will have external HDDs plugged in and I will probably strip everything down so it's just running OSX with basically no apps except for iTunes. What would be the minimum hardware specs necessary for this to run without a hitch? There is everything on eBay from 1.5Mhz to 1.83 Mhz with anywhere between 512MG to 2GB RAM and an array of HD configurations. Looking for the best compromise of optimal performance and lowest cost. Thanks for any input.