Ill toss my 2 cents in.
Like some of you are discovering, HD can be loud. They can make all sorts of sounds, fan sounds, spinning up/down, chirps, beeps, clicks, etc.
Id like to read the above referenced review on www.silentpcreview.com.
As far as fan cooling/no fan cooling for external HDs, there is no hard and fast rule. I have gone to fanless because I do not want the fan noise and have had no problems thus far. This latter doesnt mean anything, as ALL drives will fail in time, its just a matter of when
so it must be backed up. A fanless vs. fan cooled HD also tells us little: the cooling all depends on how well the fan/ventilation passages/materials/vents have been designed
theres a lot of very cheap poorly designed enclosures out there (both fan and fanless) and a low quality enclosure can also give up the ghost.
Oftentimes internal HDs will come with a longer warranty than their external counterparts. However (this was pointed out to me recently) do not put too much stake in big warranty claims, ex. 5 year warranty, it will not do you any good anyway after the drive sh**s the bed; as for a warranty replacement HD 5 years from now
think back to the drive you bought 5 years ago (10GB, 20GB, 60GB??)
5 years from now the drive you buy today will be boarderline, if not completely obsolete, based on HD capacity and features in the year 2012
hard to predict the demands of a music library hard drive 5 years from now, and Id put money that you would not care to replace the HD you are using now, with an identical one 5 years from now.
IMHO RAID is overkill for a music server unless you have $$$ to burn. After you make changes to your music library, just back it up to another 1 or 2 HDs.
Im ready to step up my iTunes and computer based music server from casual listening to more quality. I too am looking for a HD, a 500GB internal drive, which I will put into a well designed fanless enclosure. If anyone has a recommendation for a QUIET drive (speed isnt an issue) please do post it.