Western Digital just announced their new additions to the Green Series: 2.5 and 3 TB disks. Here's the WD Caviar Green, 3 TB, SATA 3 Gb/s, 64 MB Cache.
The price for the 3 TB disk might start at 220 Euros. That is about 7 cents per GB, or 13.6 GB per Euro. Compared to 4 cents / GB for the Green 2 TB, it is still not on top of the list, but will probably be there within a year.