I've read through long posts discussing the pros and cons but few facts came up. My quest is to find the most quiet drive for storing films and stuff. At least 120 Gb, never mind the performance. It's the dB per Gb ratio that matters, and in this case, particularly the idle whine.
In short: Which is the quietest big HDD?

(Many people nowadays build their computer with several HDDs. I already use a WD Raptor (isolated and watercooled) as system disc and a Barracuda V 120 AAM for storing, but need more space to look cool on DC++. Please don't start ranting about solid state or other extravagant solutions. Price is important.)

Grateful for any facts or first hand experiences.

The Samsung Spinpoint (SP1604N, SP1614N) is probably your best bet. Not only is it the quietest 3.5" drive still being manufactured, but it also happens to be quite fast, inexpensive (at least in the U.S.), and insured by a 3-year warranty.

The noise level of the drive should be similar to your Barracuda V.

I know there have been some discussions about whiny Samsungs, but I own two 160GB models (one purchased in August, one this month), and the newer one is actually quieter! So not everyone is seeing Samsung's drive quality fall through the floor. The drives don't whine, but you can hear what sounds like the idle noise of a well-behaved fan (a hiss-whoosh, comparable in volume to a good 80mm Panaflo L1A at, say, 7V?). The whoosh is more high-pitched, like hiss.

According to the notoriously correct-on-noise-matters Samsung homepage the Spinpoint V series (5400rpm) with FDB is slightly quieter than the P-series (7200rpm). For once, it also makes sense.
Storagereview also measured the V's as the quietest Samsungs. But then again, the also claim the IBM Deskstar 180GXP to emit even less idle noise... Trusting Storagereview on this is a bit like trusting a computer nerd on dating tips.

As far as drive noise is concerned best 7200RPM drives are as quiet or almost as quiet as 5400RPMs, perhaps because manufacturers now put all their development efforts into the former. But heat, which is a factor in overall system noise, is a different story. I happened upon the Samsung SV1604N article at Tom's Hardware yesterday and found this drive temp comparison of note:

http://www.tomshardware.com/storage/200 ... gb-05.html

It's 12C cooler than the next coolest drive in the test (from our beloved SP series). There are no details on the methodology but presumably it's based on idle temp.

Unfortunately, manufacturers seem to have dropped their 5400RPM drives in droves. Many online computer stores here in Australia don't even offter 5400RPM drives for sale, and the SV1604N isn't available anywhere (the biggest 5400RPM Samsung distributes here is 120GB), and when they are they're often more expensive than a 7200RPM of the same capacity. It's such a pity because these drives are cooler than their 7200RPM counterparts, perform better than 2.5" drives, and are (theoretically) the cheapest to manufacture. Although most people would consider them for auxiliary purposes like backup or video capture, they're more than adequate as primary drives. When's the last time you saw "7200 RPM drive required" on software's system requirements? I stuck with 5400RPM drives for years as my main deskop drive, most recently a Samsung SV0802N, before finally succumbing and buying a SP1614N given the lack of alternatives.

Bought a 160 Gig Samsung 5400 rpm. Runs quiet and very cool. Pleased!

(Btw, the reason you don't see any minimum specs on system demands is that most programs run anyway, once they have loaded up. But it takes longer to start programs, to boot windows, to handle pictures on Photoshop and so on. All in all, hdds have developed slower than all other computer components over the last 10 years and can now slow the system down.)

For me, a Seagate external 200 gb drive (which makes assorted loud noises
by the way) and a 16 foot USB 2 cable did the trick...

You know, I would have imagined that the Hitachi 400GB hard drive would have provided the best GB/dB.