The prices have seemed to shipwrecked on some plateau - $60-ish for low-end and $90+ for more feature-laden products.
I read some industry pundit say they believe HDD sales will fall "12%" this year and our customers have been waiting for 1-2 years for massive capacity upgrades, all holding because of the high-prices of HDDs.
Toshiba just delivered us a bakers' dozen of $125 3Tb drives, and we've used those to build two RAID5 boxes (6 drives each, with the spare drive as a "cold replacement on whichever box fails first).
Six RAID5s give us 15Tb of total storage, but we only go to 60% capacity on any RAID5, so that's only about 8Tb of actual storage. That's OK but it's still a fairly small media-center capacity for a family with kids, or a daily-working recording studio.
Even 4Tb drives would be small-ish there, and among our recording studio clients. That's why they have several, I suppose. But they're all pushing 60-65% capacities on 2Tb-disk systems now.
Sure wish those 4Tb prices would plummet, and get us into much larger capacities soon thereafter.