I would suggest you consider avoiding the Raspberry Pi and Pi 2 as the basis for a moderately high end music player as the usb and ethernet set up is not great. All the usb and the ethernet goes over a single usb controller (might even be a single usb channel?) so bandwidth, and I expect hardware interrupts, are limited. So if you are using say a USB drive and a USB sound device, they will be competing for the single USB controllers capacity. Same if you use a network share and a USB sound device, they will be competing for the single USB controllers capacity. I am not a hardware engineer though so I could be wrong about this being an issue. Just seems like a potential issue that could be avoided by using alternate hardware.
I am sure there are many happy users of Raspberry Pi as music players, just that I would think this might not be suitable in a moderately high end commercial music player. On the other hand - it might be fine.
There are other devices similar to Raspberry Pi that do not have this limitation.
If you are creating your own hardware and you add in suitable USB and ethernet controllers then you would of course avoid this potential issue.
Looking forward to seeing what you produce.