To the original question, according to the spec sheet, it's 512byte sectors.
Formatted Capacity: 1,000,204 MB
User Sector Count: 1,953,525,169
Therefore 1,000,204,000,000 bytes / 1,953,525,169 sectors = 512 bytes/sector
Source:
http://www.wdc.com/wdproducts/library/SpecSheet/ENG/2879-701277.pdf