Those WD Golds are some of the best HDD's ever made, there fast and incredibility reliable. If you have important data these are the drives.
I've been using WD enterprise drives since 2008, never had an issue with a single drive.
The fastest ones I currently have are 7K6000 512e Ultrastars that are also produced by Western Digital, these drives click a little when first activated, but i'm not worried about it, it's just the design of the drives.
For best reliability HDD's need a little air going over them. I use Silverstone FT02 cases, and have a 180mm fan running at low rpm under the drive bays.
* This is absolutely true, all HDD's even the same models sound different. There is a company in US that build very high end workstations, they use WD enterprise drives, but they select them by listening to them with a stethoscope! So they listen to the drives, and fit the quietest ones into the high end rigs!