NAS or USB hard drive to play music.

Hi all, I have alot of music ripped to my wife's laptop, windows 7, I stream via airplay aptv3 but I would also like to listen and store on a different storage device, leaves me thinking NAS or USB drive, Amp is DLNA plus is networked and has USB input, I would like to store my music on a drive in Flac form or Wav or that of a high quality rip but only use wife's laptop as a backup really. 

So once the laptop music is transferred to the NAS or USB drive it needs to be categorised so wen looking thru its library I can see album artist and not all my songs in alphabetical order! 

Fyi the router is pretty much next to my amp and all equipment and is attached wired. I prefer a wired route as it offers stability. 

So can you offer some advice on which would suit please. 

Darrell