I agree with kranewolf.....my builds usually have a SSD (120/250GB) for the OS/programs, a 1TB WD Black for data, and depending upon how many computers in the network, I place a large drive big enough to backup all of the data drives (sometimes it takes more than 1 drive). For a stand alone computer, 2 1TB WD Black drives give me perfect piece of mind.....one dies, and the backup can go into service.
I use synchback Free (free program) to backup data nightly.
You might save a few bucks by using other drives, but you won't find a better over all performance/quality drive out there.