Hard drive noise bugs me too.
There are two kinds of noise mostly, the spinning noise that the drive makes when it's running and the "seek" noise as the heads move about. Seek noise is usually in the form of rapid clicks.
Motor noise has come down a LOT in the last few years. Some drives make very little motor noise, some make more. Those with fewer platters inside often make less motor noise as do those that turn more slowly.
Seek noise is often adjustable! Many drives have a feature called "AAM" or "Automatic Acoustic Management". This is nearly always "OFF" by default.
Most drives made by Samsung, Hitachi and Western Digital have this feature. It can be turned "ON" and adjusted to various levels in many cases by using Hitachi's Feature Tool, Samsungs Hutil (Samsung drives only) or windows-based tools like HDDScan or HDparm.
Turning AAM ON vastly reduces the Seek noise but will slow down access time a little.
For example, a Caviar Black 1TB makes moderately loud Seek noise with AAM OFF but almost none with AAM ON.
Here's my favorites for low noise operation:
WD Green Power. Very little motor noise. These are pretty quiet even with the AAM OFF. Also, they run very cool which is important in an external enclosure.
Samsung. Little Motor noise, AAM is fully adjustable with Hutil. Usually a great silence choice.
WD Caviar Blue Single Platter drives- (160, 320, etc) Little Motor noise, virtually silent with AAM ON. Run cool.
WD Caviar Black with AAM ON. Little Motor noise, slight Seek noise. (Lots of Seek noise with AAM OFF)
Hitachi - Some Motor noise, especially when spinning up. Virtually no Seek noise with AAM ON. Hitachi Feature Tool allows AAM to be fully adjusted.
Drives that make a TON of noise:
Seagate 7200.10, 7200.11. Noticeable Motor noise, plenty of Seek noise, AAM not supported. Also, they run hot.
I'm sure the 10,000rpm Raptors do too!😉
WD models not supporting AAM or having AAM OFF tend to make plenty of Seek noise. WD doesn't appear to have a AAM tool. HDDScan works OK, sometimes Hitachi Feature Tool will work on WDs too.
WD usually only offers AAM "ON" or "OFF" with no fine-tuning like Hitachi and Samsung.
I haven't seen any recent Maxtors so no comment.
I vote for Green Power for an external enclosure. With AAM "ON".
Have Fun,
Keri