Summertop: I'm sure you know that, it doesn't make it any more correct though ;) A NAT router that has just one IP address will make all computers behind it appear to have one IP address, yes. But it doesn't have too.

I've got a router sitting right here that doesn't, actually. I've got all of 2001:1b40:d::/48, router has 2001:1b40:d::1, this system has 2001:1b40:d:3:2c0:9fff:fe3c:131d and other systems have... umm.. other ones.

/me hopes IPv6 is adequate protection from script kiddies