It occurred to me that Wojciech Puchar wrote in gmane.os.netbsd.general:
> even more funny - last version of FreeBSD detects built in nVidia 
> ethernet, while everything else (including Windows XP PRO X64) doesn't see 
> any device at all, not just device without driver!

On my nforce-2 based Athlon XP, I get this behaviour if I disable the on-board
ethernet. 

I think that enabling ACPI_ACTIVATE_DEV has similiar results under NetBSD.
Not sure; I haven't booted NetBSD on that machine for quite a while, as it's
my Windows box.