Western Digital’s My Passport portable hard drives have all been appealingly small and ready to take pretty much anywhere — except that they’ve depended on a computer for connectivity and power. Made entirely from plastic, My Passport Wireless ($180-$220) preserves the same compact design but is capable of fully wireless operation. A six-hour rechargeable battery and 802.11n MIMO Wi-Fi enable the 1TB or 2TB hard disk to stream media content to up…