I'd just like to point out, once again, that Netapp isn't NAC anymore, having changed from "Corporation" to "Inc." years ago. Of course, a lot of us were in the habit of calling the boxes "nacs" so it was hard to change to "nais" or "netapps."
I guess you can still call them NACs if you have a suitable acronym. "Network Appliance Computer" is fine but a little generic; "Network Appliance Cache" works fine for one product but not the other. :)
Me, I just call them "filers."
Bruce