The ST8000DM004 is the latest generation of shingled drives. While the ST8000AS0002 manged to squeeze 8TB onto six platters, the ST8000DM004 uses only 4. That's 2TB per platter. wow.
I've got one coming in Monday for testing. I'm curious about rebuild times. It's not rated for RAID but as WACO mentioned the newer generations shouldn't suck. Besides, there are inherent benefits from the additional density.
Time will tell.