Western Digital WD Black WD6401AALS 640GB 7200 RPM 32MB Cache SATA 3.0Gb/s 3.5" Internal Hard Drive -Bare Drive

Pros: Good reputation and warranty.

Cons: Slowed to a crawl after 2 years.
Was taking 15 minutes to boot and then would randomly freeze Win 7 64 bit. No indication of failure even after running WD Drive tools.

Other Thoughts: I haven't tried replacing under warranty yet. I bought a Seagate and this thing boots in 37 seconds. Not bad considering it was taking 15 minutes with Western Digital!

Pros: Its a hdd, it works, and its not a Segate

Cons: Its not one of the 4tb hdd's

Other Thoughts: I got mine in June of 2009 and it is in a computer that runs 24/7 365 give or take a few days here and there. Never had any issues with it. If you touch it after its been operating for a long period of time it is still cool to the touch.

As for the not Segate part-I have only had 2 Segate hdd's that have lasted longer then a year...one is a 20gb one that came in a old Emachines computer... the other is a 200gb that is currently paired with a p4 processor...I have only killed 1 WD hdd and it was my fault...it got dropped.

Pros: When it comes to mechanical HDDs, Caviar Blacks are the best consumer-level 7200 PRM drive out there, regardless of capacity. Great performance, dual data processors, rock-solid reliability.

Cons: Absolutely none.

Other Thoughts: I swore by Seagate for years. Their mid-2000s Barracuda drives had me hooked. Then I got my first 640 GB Caviar Black and that changed everything.

I had two of these striped in RAID 0 for a while, but I accidentally bricked one of them, my bad. Still using the older one of the two I had as we speak. Love it.

Pros: Best drive I've had, lasted 4 years, 2 retrofits, absolutely no problems! Grabbing a 2TB WD Black here in a few days!

Cons: Smaller than what I need now days

Pros: Cheap, you get what you paid for

Cons: bought 2 and all failed

Other Thoughts: as soon as I finished format both drives, they all gave out high pitch tone, and it's so loud, I could hear that loud pitch tone feets away, this is so wrong, I sent them back for RMA, see what they are going to solve this issue, I think this is an known issue so to speak.

Pros: Was good while it lasted, RMA process seems okay, haven't gotten new one replaced yet.

Cons: Some data lost

Other Thoughts: Got "Too many bad sectors" error. Some data was lost but only the parts on the bad sectors. Was able to pull all other data off, so that was good.

Pros: still running all day and night since I bought them back on 11/27/2009

Cons: none

Pros: They keep replacing it.

Cons: they keep going bad, constantly clicks then fails to the point of corrupting files, complete os failure

Other Thoughts: First one last about a year, the second a few months and the most recent only a few days. Have tried with multiple formats and operating systems. If the failure wasn't enough the clicking of the drives would drive me mad.

I would buy other WD drives, I've done some research and these black drives ate just notoriously bad.

Pros: Great Drive! This drive has been used almost daily for the past three years and formatted several times without a single issue. Has great cache and a decent amount of storage space. Quite and fast its by far the most reliable drive I have yet to own.

Cons: None. Well it could clean up around the house more often.

Other Thoughts: "Black Edition" makes it BA lol.

Pros: Going strong still after heavy use.

Cons: None.

Other Thoughts: I can't speak highly enough of these drives.