"Boxed" vs. "OEM":
Boxed is boxed for retail sales. That includes the fancy packaging and any/all software.
OEM is for resale as part of a complete system. Most often in a plain white box without any software.
If you need any software for mirroring/formatting, you should be able to download it off the manufacturers website, but be aware the warranties are almost always different between boxed & OEM products.
Personally, for hard drives and DVD/CD players, I watch for local sales so it can be brought back if it was dropped during shipping. Most everything else *I* buy is boxed.