I currently have an Airport Extreme and a NAS (connected via ethernet) where I store my iTunes library and iPhoto library. I've got Time Machine to currently back up my macbook to a USB connected drive to the AX.
I was thinking about getting a Time Capsule instead but I was curious as to whether TC is able to back up USB connected drives as well as the macbook. If so, I'd move the iTunes and iPhoto libraries to a USB drive, with the added benefit that I'd be able to access them via Back to my Mac.
was curious as to whether TC is able to back up USB connected drives as well as the macbook.
Not sure what you are asking.
Time Machine can back up the Mac and a USB or FireWire drive attached directly to the Mac to the Time Capsule.
Time Machine cannot backup a drive attached to the USB port on the Time Capsule. You would need Carbon Copy Cloner or SuperDuper for that.