External Hard Drive

What makes/criteria should I be bearing in mind when seeking to buy one? I know of:

• Physical durability
  
• pomegranate-proofness
  
• Fast data transfer (does my other drives being ATA/SATA/eSATA/blablabla factor in here? How do I tell what data type my other drives are without opening the CPU up and looking at its cord to get a compatible new drive?) I remember CPU-Z, brb trying none.
  
• Installation (isn't it just plug and play?)

I'm as clueless as ever when it comes to hard drive, help pl0x.
Oh, looking to spend around $130 or getting a 500Gb drive, that or the better offers there are (e.g: $130 for 1TB drive).

Portability:
2.5 inch external harddrives allow more portability, since it doesn't need external power.
3.5 inch external harddrives require external power source, so less portable.

Bang/Buck:
2.5 are more expensive per unit of space than 3.5

Performance:
most 2.5 are slower than 3.5. Though this totally depends on the harddrive themselves.

ATA/eSATA/SATA/wtp
These days, SATA is the standard. So when you look for a drive/enclosure it's almost guaranteed that it'll be SATA to SOMETHING.

The SOMETHING can be USB 2.0, 3.0 (of course all backwards compatible) and eSATA and firewire. USB 2.0 is the most popular choice right now, with more computers coming standard with eSATA ports, you might see more of this in the future (because eSATA has a larger theoretical bandwidth than USB 2.0, one might argue that 3.0 is better than eSATA but it doesn't matter due to the harddrives being the bottle neck).

That SOMETHING can be two or more things. Example: a enclosure could have multiple connectors (eSATA, USB, firewire) for compatiblity.

When it comes down to buying a already made External harddrive or a DIY one, the DIY ones are often cheaper and offers more peace of mind, since you know the kind of harddrive you've used.

I did some reading about the USB and found this:

Signaling

USB supports following signaling rates:
A low-bandwidth rate of 1.5 Mbit/s (~183 KB/s) is defined by USB 1.0. It is very similar to "full-bandwidth" operation except each bit takes 8 times as long to transmit. It is intended primarily to save cost in low-bandwidth human interface devices (HID) such as keyboards, mice, and joysticks.
The full-bandwidth rate of 12 Mbit/s (~1.43 MB/s) is the basic USB data rate defined by USB 1.1. All USB hubs support full-bandwidth.
A hi-speed (USB 2.0) rate of 480 Mbit/s (~57 MB/s) was introduced in 2001. All hi-speed devices are capable of falling back to full-bandwidth operation if necessary; they are backward compatible. Connectors are identical.
A SuperSpeed (USB 3.0) rate of 4.8 Gbit/s (~572 MB/s). The written USB 3.0 specification was released by Intel and partners in August 2008. The first USB 3 controller chips were sampled by NEC May 2009 [12] and products using the 3.0 specification are expected to arrive beginning in Q3 2009 and 2010.[13] USB 3.0 connectors are generally backwards compatible, but include new wiring and full duplex operation. There is some incompatibility with older connectors.[citation needed]

Are there similar transfer rates for the rest, just for comparison's sake?

Also, is overheat a risk to look out for with externally powered drives?

Thanks XL, I think I almost got it now.

Do you want to just BUY one from say BestBuy or "make" one yourself?

USB 3.0 requires your computer to support it, same with eSATA. Well, eSATA really just needs a external port.

Basically External harddrives are "Normal" harddrives + chassis.

To make one you pick a harddrive, then buy a chassis and BAM external.

Well it's not for me, so buying from a store is the only option.

Also,

If several devices are connected on the USB hub and working in parallel (for example, a webcam + a USB flash drive + a mouse), then the USB bandwidth is shared among the devices usage.

Is it advised to discontinue using other USB-connected devices if you want your bulk file transfer to go through faster? Or does it not matter that much?

EDIT: Interesting, I have a spare Hard Drive lying around, might as well try making an external one.
Oh, does that chassis mean I'll have to mount it to my motherboard and that's it?
Nevermind this. It doesn't matter that much for now. I'm only looking for precautions/suggestions regarding buying a brand new one.

Something like this: http://www.newegg.com/Product/ComboDealD...mbo.377687

Or this: http://www.newegg.com/Product/Product.as...6822136395

Both of the above require you to plug in the harddrive to a power source other than USB

but these you don't (but more expensive): http://www.newegg.com/Product/Product.as...6822136477

I'm interested in this one http://www.newegg.com/Product/Product.as...6822136477 but I'm not really digging the backup feature. Does reformating the drive get rid of it, along with other frilly softwares it comes with? If not, is there an easy way?

Yes, it's just like a harddrive on your computer, reformatting it would get rid of everything. Just be careful to not do anything to alter the firmware.

The special points which I had in my mind at the time of purchasing my External HDD are:
Technical Specification:
In order to ensure maximum compatibility with most desktop and notebook computers, the StoreJet 2.5 mobile uses a high-speed USB 2.0 interface, which provides data transfer rates up to 480Mb per second while offering the convenience of plug and play.
Features:
To protect against data loss or damage from accidental slips or falls, the StoreJet 2.5 mobile meets the U.S.military drop-test standards MIL-STD-810F with advanced two-stage anti-shock technology, literally making it one of the safest places to keep your data.
Specifications
Package Contents
Accessory
System requirement

Oh, looking to spend around $130 or getting a 500Gb drive, that or the better offers there are (e.g: $130 for 1TB drive).

If you want the best bang for your buck, you could keep checking:

>>> http://slickdeals.net/sdsearch.php?searc..._archive=0
- until you see a deal you like.

From a quick browse through, it looks like you can get a (decent performing) 1 TB external for about $70-80 (after rebate) if you're willing to wait for such deals. Also, check e-tailers at resellerratings if it's one you have no experience with. And then you can usually save a little more for this type of purchase through Bing's Cashback.

More reviews for that hard drive

http://www.tigerdirect.com/applications/...VIEWS#tabs

(I prefer tigerdirect, but i guess its all in "Who is cheaper")