Solid State drives use flash memory just like what you would find in a USB stick, phone, or mp3 player. SATA3 SSDs like the one above are about 10x as fast as 7200RPM mechanical hard drives, so they are preferred for faster OS loading and game level loading speed. SSDs were very expensive when they came out several years ago but now they are dirt cheap considering the performance output. Generally people buy a SSD when first building a system, load windows and favorite games on it, and add a HDD later for bulk files like movies and music. Alternatively you could store bulk files on the cloud.
tl;dr get a SSD. It will make you happy.