My current set-up consists of an old MBP that I leave plugged in to a 1TB drive that holds all of my media. I also have an MBA that I primarily use for browsing and working, but all media is relegated to the MBP and the external, wall power-tethered drive. Now, I just received a WD "My Passport" to provide another backup and to take the aforementioned media with me when I leave the house with the MBA, so I'm wondering about the best way to keep both of these drives "current" (I regularly add new music). The only way I can think of doing this is by managing them separately, but I feel like there's a more efficient way of doing this. Should I bother with the pre-installed WD software, or just use the OS X Disk Utility? What's the best way to keep my respective iTunes libraries synched up? I purchase most of my music from Amazon, unfortunately. Thanks!