Is "no span port configured" sufficient to prevent someone captures traffic intended for another device, specially someone's password, using sniffer software (e.g. ethereal) running on PC connected to the same LAN?

Hello,I am in the process of ordering a 3800 series router for Japan. I've never ordered internet connection out-of-US before. what are some of the concerns I should be addressing with Japan's ISP?I also would like to know what WIC is appropriate f...