NetBIOS is an ancient session-level interface and transport protocol developed by IBM to network together PCs. It is a broadcast-based, non-routable and insecure protocol, and it scales poorly mostly because it was designed with a flat namespace. Since the late 1980s Microsoft has adopted NetBIOS for their LAN Manager product, and from there it found its way into early versions of Windows and all the way into Windows NT.

via Disable NetBIOS in W2K/XP/2003.

Works with Windows 7 and got rid of all NBNS traffic for me on a per interface basis.  I have netbios disabled on the wireless interface  because wireless should be considered insecure and this NetBios traffic likes to broadcast to everyone your position which IMHO is not good.  Run silent, run deep.