List the different data types and give an example where each would be used?

b, bytes: The smallest data type, isn't used very much when you're talking about files but it's the ground.

kb, kilobytes: In one kb there's 1000 bytes. A document is often some kbs.

mb, megabytes: In one mb there's 1000 kilobytes. This one is more used than the previous. A song is usually 3-6 megabytes big. A movie in dvd-quality is around 700mb big.

gb, gigabytes: In one gb there's 1000 mb. This is also used more. A movie in HD is usually 4 gb, a bluray is 8 gb or more. Todays harddrives holds 250-1500 gigabytes, where 500-750 is most common.

tb, terabyte: In one tb there's 1000gb. This isn't so common, but harddrives in different kinds usually holds around 1tb.