Which External HD? (in Off-topic)

Ok, so I need an external HD for my movie files, but am stumped on what Hard drive to purchase.

http://www.amazon.com/Seagate-FreeAgent-GoFlex-External-STAC3000100/dp/B003SU35M4/ref=pd_cp_e_1

or

http://www.amazon.com/Western-Digital-Essential-Desktop-External/dp/B0042Z55RM/ref=pd_cp_e_2

Or if anyone has an idea for something better or can find these cheaper, it would be much appreciated!

My Seagate external died on me last year and WD gets better reviews on theirs.
http://www.newegg.com/Product/Product.aspx?Item=N82E16822136471
Only 2TBs, but it's on sale. ;p

That was my next question, are there any that dont need the wall plug? This will be my first external, so I wasnt sure.

all of the full size external hard drives will need an ac adapter, they are also the fastest (especially if they have a 7400 rpm hard drive inside) and most reliable over time.

the portable ones will use laptop drives and can usually work off of the usb drives power. these drives are typically slower and will not last as long on average. if backing up large amounts of data the speed can make quite a bit of difference on your time needed for backup.

I've got an older WD, 1TB model and it's lasted me a few years with no problems. I regularly run things directly from it and there's no noticeable delay. It runs off it's own PSU which is a little annoying in terms of wires floating about especially in the mess of cables that is my home office, but not majorly so.

In the industry of selling these things to people, I generally regard the large brands (WD/SG) as equal. Samsung hdds have been acquired by Seagate (Which means I love it when people badmouth Seagate and praise Samsung, given that they're exactly the same product these days).

In personal experience, WDs are better, provided they aren't WD Green. WD Green drives can burn in fire and I avoid selling them if possible. Even at the detriment to my company.

Regarding the USB powered drives, the only current ones I have experience with are the Seagate Expansion drive. The way I use it is to dump everything I am watching onto it as a copy and just delete it after I've seen it. It's very slow sometimes (as dude earlier mentioned), taking almost a minute to load some files for no apparent reason. I do think this is just due to USB power and read speed, though...

Anything over half a gig should require an a/c adapter. There are some that avoid it by using two USB ports for power, but I strongly suggest you stick with a 110v instead. My experience with running external HDs from dual USB ports is anything but reliable.

As far as which of the big names to pick from, they're close enough to equal. But remember that if there's an electronic failure in the power supply or case electronics after a year or two, it's normally not a big deal. You can pick up HD enclosures for a small amount of money and just swap the drive over.

The larger units (ie. the wall powered ones) will pretty much always have less problems than the single USB powered units. The products that people base their review between the brands is generally between these larger (ie. 3.5) ones.

I honestly can't think of a fair comparison between laptop sized models.

"Anything over half a gig should require an a/c adapter. There are some that avoid it by using two USB ports for power"

Even with that limitation, that is ludicrously expensive comparatively and you would usually have to custom make it from the drive and an enclosure, as the larger companies wont support it. A lot of the add the second USB to smaller drives just in case people need it for those, which they shouldn't.

You usually only need the second one if you already put too many devices that require USB power on your machine.
But the warnings of USB low power should be arriving at your desktop already at that time.

what i usually tell my customers is to only get the smaller portable drives if you mean to carry it in your shirt pocket or laptop case continually.

even then i still recommend that most have a full-sized backup drive at their home or on their desktop computer.