a) The Ex Cases come in dual protocols so you can use Firewire (which is faster) and USB Hi-Speed and Full if you want to transfer to OP's that do not have either Firewire or USB Hi Speed
WesternDigital has dual (USB and IEEE1394) externals, Maxtor probably does too.
b) You can still find HD's that can be used and have a full 3yr warranty whereas the readymades come with 1 yr that I know of
I don't know about the warranty to be honest, I never looked, but 1 year is probably right.
c) Upgrading to more Gigs is possible so it is able to grow with your Data
You can probably do this with a "ready made" as well, if you were so inclined.
d) In most cases) You can get 5 1/4" in size 1's so adding optical drives is possible (ie Burner)
If he put a burner in the external case, where does his hard disk go? I would assume if he needs a burner, he'd need to buy another case anyhow, or buy either an internal or external burner.
Externals are basically internal drives put in a "pretty" case, so they are prone to the same problems and are just as reliable as an internal drive. However, it
may be a little less expensive to buy the components (case and hard drive) abd assenble the thing yourself.
\Dan