Potential win ...
If it's anything like the 1Tb series 'Green' drives that I've got in my NAS box then the claims of quietness and meagre power usage are bang on the money.
In fact, the drives are so quiet that when I first fired them up I honestly thought they were DOA because I couldn't hear them spinning up. Granted, they're not the fastest drives on the planet, but they do their job with a minimum fuss. As for power draw, all I can say is that the NAS box pulls less than 25W under load and it's got two of the 1Tb 'Green' drives in it - that's good enough for me. They seem to run fairly cool as well - the NAS has a temperature controlled fan inside and it only ever really comes on when the drives are getting hammered (eg. during big file transfers and backups)
The only downside I can see is that 2Tb of data is a helluva lot of storage to potentially lose, backup regimes or no, and I'd be very wary of using one as a sole drive. But then, that's me.
I don't really care if the Seagate drives pull less power and/or are quieter - after the Barracuda firmware debacle they're off the supplier list for home and work purposes.