Getting high for HDD is quite normal in small factor pcs. I get around that with my NUC aswell so i think this is normal. By the way with my Zotac Box i get also high HDD temps. These pcs are not built to run the whole day so i don't see a problem in high temps. What you can do to get your HDD a bit cooler is to buy a 5200 rpm HD because they run a bit cooler. And to solve high temps of HDD you can always add a SSD.
I can see why you are a little bit worried, but what @philipp8899 says is right.
Basically, laptop hard drives (form factor of 2.5) should run between 5 and 60 degrees Celsius without experiencing any major problems. Usually, laptop HDDs run a bit hotter than desktop ones (form factor of 3.5) because laptop hard drive docks have less cooling airflow than the desktop drive bays. Since your NUC is a small form factor PC, it should also have a bit less cooling airflow.
Still, the 5 to 60 degrees Celsius is considered as safe operational range.
In the link below you could see the Spec Sheet of the WD Scorpio Black HDD and on its second page under "Environmental Specifications" you can see the normal operational temps, which are shown up to including 60 degrees:
If you are still concerned whether your hard drive is healthy or not, you could always perform a check on it. You could use the WD Lifeguard Diagnostics Tool:
Otherwise, @philipp8899's suggestions are also good. Smaller RPM hard drives perform a bit cooler and SSD's are always an option. It depends on what you'd prefer.
I hope I was of help!
Best of luck!
Thanks for the reply.
Yup! Looks like I didnt think things through while ordering the 7200rpm drive As for now I have two solid blocks of copper the length of the drive stuck to the label side of the drive with thermal paste. Seems to be keeping it 10c cooler. But still high. I may go the route of eSata external, because my external drives are much cooler. We'll see!
Curious if WD's feature Reduced Power Spinup will benefit me at all with operating temperatures? Will it reduce it while only spinning up or while operating the whole time?
The RPS is WD's optimized spin up feature. 2.5-inch drives are configured to spin up using minimal power consumption. This is triggered (when the certain jumper settings are made) during spin up and not through the whole operating process of the HDD. The specific focus was to minimize the duration and magnitude of the peak power consumption from the hard drive and it would perhaps slightly help with high temperature problems. This is only necessary, though, when the power supply may not be able to support the spike in power consumption during boot up.