I have an IMac with a 500 GB hard drive which has all my music, pics and movies. There is about 160 GB available but I still have more movies that I could rip but I have hesitated as I don't want to fill up the drive too quickly. I also have an external USB 500 GB drive which serves as a backup using Time Machine. I am considering getting a 1 TB external firewire drive to hold all my media with plenty of room to spare. Is it reaonsable to use the 500 GB drive to back up music and movies and keep pictures only on the IMac drive? Do I lose any streaming quality to my ethernetted ATV by using an external drive vs my IMAC? Should I look into a NAS? Will the new software let my sync a particular movie from my external hard drive to my ATV to avoid any streaming issues? I'd appreciate your input.