So I thought it was timely to add a quick chart of the current state of affairs in storage:

before we start, some rough idea of the size of some things:

1 character			=1b (byte)
1024 characters	3 pages of text		=1kb (kilobyte usually pronounced "k")
Approx 1 million characters	1 small text encyclopedia	1 digital camera image	=1Mb (Megabyte usually pronounced "Meg")
Approx 1 billion characters	1000 digital photos	1/4hr of video	=1Gb (Gigabyte usually pronounced "Gig")

and here are some things to put all that data onto, along with some rough prices:

Floppy Disk	1mb	$1.00
CD-R	700Mb	$0.50
DVD-R	4.3Gb	$1.00
512Mb Memory Stick	512Mb	$20.00
4Gb Memory Stick	4Gb	$66.00
Pocket Hard Disk	120Gb	$165.00
3.5” External Hard Disk	320Gb	$186.00

There are lots of reasons you cant directly compare each of those items, like speed, size, durability and rewritability, which means that some media types are better than others for different purposes.

For example: 75 DVDs will hold the same amount of information as a 320Gb Hard Disk, for a fair bit less money, but you can only write to the DVD once.