I want a quiet 2.5" HDD. I'd like to get the Western Digital Scorpio Blue 500GB. Is that a quiet drive, or are there issues with frequent head parking and/or spin up/down noises?

Seagate Momentus XT hybrid drive......http://www.silentpcreview.com/article1071-page5.html SPCR test of older model, new models are out and have more SSD memory, but I have two of these in two desktops and they are fast and silent relative to any traditional HDD.

Thanks. The Seagate Momentus XT seems very nice and FAST, but also more money.

Listening to those audio recordings, the Scorpio Blue seems quieter than the HD502HI, which I have and never hear (except for at boot or shutdown).

So it seems I don't need anything quieter than the Scorpio Blue. My only concern with the Scorpio Blue is the heads parking and spinning down frequently if that cannot be controlled.

i have a blue 2.5 1TB drive in my PC at the moment. Easily the quietest 2.5" drive i've ever had, but still audible. Head noise is also pretty low as well. If you are worried about drives spinning down, theres an option in windows power settings to never power down the drives. I however set mine to power off after a minute, so 90% of the time they're never on!

Is this being used as a main (OS) drive, or additional storage?

Thanks. I currently use the Window settings for controlling spin down on the HD502HI and it works fine. I just read somewhere that in the Blue the spin down control is done at the firmware level in such a way that it cannot be controlled in software by the OS. I suppose that might have been for Mac OS (or some other OS) or just not true. But that is my concern. As long as it can be controlled by Windows, I'm fine with that.
This is for data storage/files/projects. The main OS/System/Applications drive is an SSD.

Well, I got the WD Blue 2.5" and installed it. This drive spins itself down regardless of hard disk sleep settings in Windows 7 or Mac OS X. So unless the drive is actually reading or writing it is not spinning. This is really annoying because there is a noticeable delay anytime you access the drive while it spins up and makes noises spinning up and clicking.
Unless I can figure out a way to permanently change this behavior, I'm going to return the drive.

Are you sure the disk actually spins down, and not just parks its heads?

WD has a utility called WDIDLE3 that can be used to disable the idle timer. Not sure if all drives are supported though.

I'm sure I'm hearing a spin up sound. I'm also hearing clicking sounds that could be the heads parking.
The lag/delay and noises are worse in Mac OS X than Windows, but neither is acceptable for any sort of use as a data storage drive.
I'll probably just return it.

I'd really like to find a 2.5" drive that doesn't have these issues. But if none exists I suppose I'll just make do with the my old drives for the time being.

Many 2.5" HDDs do the head park thing, but instant spindown is a new for me. But I rarely play around with 2.5" HDDs and the only 2.5" HDD I have my hands on right now is a WD Black 160GB. Came with my netbook, which now has a small SSD.
The WD Black behaves, doesn't even park it's heads it seems, but it's a 7200RPM drive and far from quiet.

Instant spindown is new to me too, and it's extremely annoying. The best way I can describe it is it's like using a CD-ROM drive. Whenever you need to access it there is a delay while it starts spinning the disk. I don't know how anyone could tolerate this sort of thing from a HDD.

I removed it and put my Samsung HD502HI back in and what an improvement! I suppose I'll just make due with the "big" drive until I find a 2.5" that I really like.

Oddly enough, I was having the same issue with my older 3.5" WD Blue 640GB. My OS and apps are on an SSD and my media library resides on the HDD. While listening to music, the s/w buffers a song or two, and the damn HDD spins down sometime before the next track starts....which leads to a delay between songs while the HDD spins back up.

I own 4x Hitachi 5k500b and imo they are very quiet, they were reviewed by SPCR and got silver awards, its a nice drive, not that much vibration, nor noise.

I would wait to see how are the new WD reds 2.5, maybe SPCR also can get some.

I bought 3 2.5" hard drives
1 x WB blue 500gb
1 x Hitachi 7k1000 and one 5k1000

All are quiet, with very little vibration.
The 7k1000's performance is superb for a hard drive with a big buffer, faster spindle speed making it ideal as a boot drive.
The 5k and WD blue are both good and similar performance/noise wise

Get a 7k1000 2.5" I'm impressed it's performance was superior to a 3.5" 7k1000c
But with very little noise and vibration.

I have hitachi 2.5 7k1000 and its a great drive, but it does vibrate much more than my 5k500b and 5k750, no seeking noise that i can hear and its a good drive, specially since it performs well.

One drive that i want to test is the just released, HGST Travelstar 5K1500 but i fear the triple platters.... but i would love to have 1.5tb.

I've got both side by side, and there is very little vibration off of either the 5k or the 7k drive. I have mounted them both in a Scythe Twin Mounter 2.5 Rev.C fitted to the 3.5" bay of a Sileo 500 which also has some rubber mounts for the HDD bay.

The drives are effectively inaudible even during intense HDD activity. You can only get a very very slight seek noise if your ear is very close to the case.
I have no hesitation recommending either drive, but the 7k's performance is surprisingly good and better suited for the OS and as a boot drive.

Drives can vary in noise one of my 7K1000C 3.5" drives is certainly stronger vibration and seek noise. The WD blacks are also hard to tame in vibration and seek noise too. I was going to try the green series, but for fun I gave the 2.5" Hitachi 7K1000 a bash, so far I'm impressed it gives up nothing in performance to most desktop drives, and it's very quiet at least in my set up.

I see some new bigger 2.5" drives out recently WD20NPVX 2TB for one. But bigger (not a problem for desktops)
I'd wait for less platters and lower prices myself. 1TB is quite a lot for most folks just add another drive.