i have 320g hd on my i-mac and a 500g external usb hd that time machine backs up to. the internal 320g is staring to get full and was think of adding another 1T external to store only media files (pictures,home videos). how would time machine work having two externals? is there a better way to address storage without having to replace the internal hd? Would a network hd be a good idea since I would also like to share media files with other windows machines on the network. Thansk in advance, MAC newbie so any advice would be greatly appreciated.