What's better music source: local HD or NAS?

What are the sound quality advantages of getting music off a local drive rather than streaming it off a network drive NAS via hardwire in your house? I can go both ways and am not sure what's better. Coming off either a Mac Mini or a PC. To the local drive, I can go firewire, Esata, or USB. Thanks.
Not sure. I asked the question to the guy building my CAPS 2.0 server, and he said not difference. If you have a buffer in your music player (like JRiver), I don't see how there could be any difference, because you are just putting untimed bits into a buffer.