My notebooks, on the other hand, are little, one-drive wonders. Since I'm too spoiled by the speed of SSDs, I had to use 500GB SSDs in them to avoid losing storage space. The notebooks are used just for travel (and emergency backup for my desktop machine) so I don't need as much storage space as my desktop machine.
I've found the speed of data access on the WD Blacks in my desktop to be plenty fast for me. SSDs wouldn't really be much of an improvement unless I was moving large chunks of data all at once. The times I do need to move a large amount of data, I just start the process, then go do something else, like make a pit stop, grab a snack, take a nap, watch TV, etc., stuff I would want or need to do anyway.
My backup drives are pokey 5400rpm WD Greens. Since they run only around and average of ten minutes a day each, I don't mind how slow they are and love how much less they cost. I run my backups while watching the news on TV so it's not like I'm having to stare cross-eyed at a monitor bored out of my skull while waiting for them to spin up and index.
I'd rather just see SSD prices be on par to hard drives. My hard drives could stand to be replaced by SSDs, only if the 3 TB ones were only $200!
backup drives if a drive goes belly up in my desktop machine while waiting for a replacement drive. If the SSD in one of my notebooks dies, I can always use another notebook until I get it replaced. If it dies while I'm on the road, I can swap it out with one of my backup HDDs I carry with me (I carry two backup HDDs; one is a clone and the other is for images and new data; I also backup new data on the clone).