Australian stores began to sell 2 terabyte hard drives from Western Digital. For the first time Western Digital is trying to pull off such big capacity hard drives while competing with Seagate, which used to be number one on the market making 1.5 terabyte hard drives.
Western Digital hard drive is included in the Green Products line, because it uses a lot less energy due to speed variation (from 5400 to 7200 RPMs). Unfortunately, the green product idea may have a negative impact on the hard drive production comparing to other similar capacity hard drives. 3.5" WD20EADS also has a 32MB cache and costs $250.
In the near future we can see this product leading the marketplace because Seagate is not planning to launch anything bigger than this, any time soon. As for Samsung, they chose not to compete in terabyte market right away.