I have:
a Crucial M4 128gb SSD (OS/Games)
a WD Black 320gb HDD (Docs/usr data/ etc.)
I also have two external HDDS:
a 1TB My Book I got back when 1TB first showed up. (around 2007 iirc)
and a 1TB My Passport Essential my brother got me last year.
Both are almost full at 10.3GB/17.1GB free of each.
Now here's why:
...
hmmm....
well I got the SSD because I wanted the speed, I'm a pretty unpatient person
and the 320gb black was there when I got the PC.
and the two external drives are for my media/mass storage, tbh I didn't prefer WD over Seagate but the price was about right and seagate drives are hardly available over here.