WD announced the WD Pro hard drives are now available in 5TB and 6TB capacities. The award winning HDDs are ideal for NAS systems that have up to 16 drive bays.
I recently purchased a 13 inch 128GB MacBook Air a few months ago (my first foray into OS X) and only recently did I feel the internal storage was not enough. To begin with, you get to enjoy less than that because part of it is allocated to OS X and installed apps. When the movies and pictures started piling up, I quickly realized that I need more space.