I disagree. There are subtle but significant differences depending on the model and capacity.
speed of 7200rpm - Samsung F3 - low temps/power - great speed
Hitachi - good speed - in middle in terms of low power/emps
WD Black - high speed almost as high as Samsung at cost of more power
Seagate - questionable QC - decend speed - some say higher read times - Seagate tools a plus
WD Green WDxxEARS - Advanced Format design - need to align partitions or drive performance suffers considerably - really low power and low temps - lowest of any drives available - should be good for storage if you align partitions - can be tricky in XP and Linux - some reports of same issue as WDxxEADS while others say it's not a problem
Hitachi - no 5400rpm - 2TB drives are 7200rpm and have high temps/power - decent performance but not most efficient drive
Samsung - imho, best of the legacy 5400rpm 'storage' drives - low heat/power - typical speed for a 5400rpm but it's for storage
To answer the OP's original question: imho, best 2TB drive is this one:
Personally I have had terrible experience with USB external drives. I have never had one last for more than 30days past the warranty. Most external HDs have a warranty of only 1 year. My dad has personally lost so much data to external HDs it is not funny. I personally would use any good standard HD and mount it in an external case before ever buying a external HD to backup/archive my information on to.
If you are looking for internal, you need to consider
1) Wat am I willing to spend?
2) How critical is the data I am placing on this drive? The more critical the data, the more you need to look at warranty, possible RAID, and MTBF on the drives.
3) Is it going in the computer or am I mounting it outside?
4) If outside, what method to I use to connect the drive(s).
Personally I have had terrible experience with USB external drives. I have never had one last for more than 30days past the warranty.
I have six external USB drives that were pre-assembled, and four more that I created by buying bare drives and putting them into an enclosure. I've been using two of the six pre-assembled drives for almost six years, and two more of them for almost 5 years. I've never had the slightest problem with any of them.
There are subtle but significant differences depending on the model and capacity.
"Subtle" differences was what I was keying on since the OP's question suggests he just want capacity to store files and isn't really looking for anything special in a drive.
The biggest difference would be between the 5400rpm "green" drives and the 7200 rpm "standard" drives. The "green" drives will generally be cheaper, and therefore given what I'm thinking the OP's requirements are, probably more appropriate.
I would be adding it internally im making a cheap WHS to access anywhere while im away. i would be adding them internally then when i run out of sata ports ill add external ones. in your opinion which brand holds the most reliable hdd you have owned? Would a green hdd work or would i need a 7200 hdd? Thanks for your answers so far they have been really helpful