id also go for an esata drive. currently i have a 500 GB WD one similar to the one in the first post only it had usb 1.0... just yesterday i moved ~67 GB of files to it and it took 110 minutes, alttle more than 10 MB/s.
if your motherboard dose not have esata then its no problem with this sata to esata converter http://www.newegg.com/Product/Product.aspx?Item=N82E168...
The MX-1 enclosure comes with a sata to esata bracket....one hell of a fan....and if the enclosure or HD dies you just have to replace teh one that died not both. I happen to use this setup on the Gigabyte p35-ds3p and have been running it as my main drive for over six months. HDTach says I lose a few MBs on speed but not enough to be worried.
eSATA peak communication speeds are 150 or 300 Mb/s (depends on the device), BUT you'll never see that speed for sustained use. Real performance measurements show average data transfer rates around 30 Mb/s for USB2 connections, around 40 or better for eSATA and Firewire 400 (aka IEEE 1394a), and even better for Firewire 800 (aka IEEE 1394b). So although you will not, on ANY of these systems, see peak performance, there are real meaningful differences among them. Oh, and for a reference point, some tests I've seen say that a decent eSATA enclosure on a real eSATA port, and holding a SATAII drive, will perform at almost exactly the same speed as an internal SATAII drive.
Whether you get a case and drive separately and assemble (easy to do) or buy a finished external drive, I'd look for these:
Dual (USB2 plus eSATA, or USB2 plus IEEE1394a (Firewire 400)) or triple (all three) interfaces available. Gives you maximum flexibility and portability to use your unit anywhere.
Its own power supply unit - almost impossible to get a case for a 3½" HDD without that, now. Most larger HDD units pull more power than a USB2 port alone can supply.
On / off switch on the case to turn off when not in use.
Built-in cooling - ??? Some say it's really useful, I don't find it necessary. Depends a lot on which HDD you have and how warm it gets in sustained operations. My case does not have a fan, and runs fine with a 500 GB Seagate unit inside.
A word of warning about SATA to eSATA "converters". Many are just cables with the right connectors on the ends and a mounting panel to make the eSATA sockets available on the back of your case. These will work just fine for most people, minus a few features you may not need. True eSATA includes some things that you may have already in your SATA mobo controllers, or may not, and you'll never know. The most important to consider are cable length and hot plugging. eSATA allows longer (than SATA) cables from computer to external case. And it is supposed to support "Hot Swapping" so you can disconnect the external drive while the computer is running, as opposed to needing a proper shut-down of the whole system. Sometimes those things are in your SATA controller anyway, sometimes not. But if you never need those features, the simple adapter cable system is just fine for you.
First of all, eSATA is an interface system between your mobo and an external box containing a device. It is NOT part of a bare hard drive system. So, for example, when I put mine together I bought an external enclosure that connects to the computer via either eSATA or USB2. Now, inside that enclosure I made sure it would accept a SATAII hard drive, and I bought a Seagate 500GB SATAII unit. Note that the Seagate drive knows nothing about eSATA - that is a property of the external enclosure, not of the drive unit.
How to install a standard hard drive (there is no difference between internal and external) in an external case is normally easy and described well in the instructions that come with the enclosure. So-called "External Hard Drives" just mean they are a finished unit that consists of a case with a "internal" hard drive already installed inside and ready to use. If you want to look at installation instructions before buying, try looking up the external enclosure manufacturer's website and see if they can show (or download) a copy of that instruction sheet.