Yes, nothing wrong with putting a "NAS" drive into pretty much any situation, including a desktop system. The only difference there is that a "NAS" drive with TLER will not try as hard to recover data in the event of a "bad sector". In practice, I haven't really found the extra effort taken by a "desktop" drive to help at all, so go for it!

WD also has "Red" NAS drives in large sizes, plus their "Purple" drives labelled as "for surveillance systems". As near as I can tell from using one, the Purple drives are the same as the Red Drives, but with the addition of the ATA Streaming Command Set. Most software outside of a dedicated PVR/Camera recorder will just ignore the extra "Streaming" commands, and all of the normal capabilities are still there.

Cheers
-ml