Byte – one grain of rice
Kilobyte – one cup of rice
Megabyte – 8 bags of rice
Gigabyte – 3 container trucks
Terabyte – 2 container ships
Petabyte – covers Manhattan
Exabyte – covers the UK (3 times)
Zettabyte – fills the Pacific Ocean
(h/t to David Wellman at Myriad Genetics)