The very first production hard disk was the IBM 305 RAMAC (Random Access Method of Accounting and Control), introduced on September 13, 1956. This beastie stored 5 million characters (approximately five megabytes, but a “character” in those days was only seven bits, not eight) on a whopping 50 disks, each 24 inches in diameter! Its areal density was about 2,000 bits per square inch; in comparison, today’s drives have areal densities measured in billions of bits per square inch. The data transfer rate of this first drive was an impressive 8,800 bytes per second. (source)
I just checked: 64GB SATA III MLC Internal Solid State Drive costs $95.00. Ha! I’m waiting for the cost to come down a bit.