The exact size, of course, depends on the playing time (in minutes and seconds), on how good the original compresses and the compression quality. 1 Mb a minute is a good approximation, in practice. I wouldn't trust 2 Gb to hold 1000 average downloaded songs. Just go for 4.
The causes of the Vietnam War were derived from the symptoms, components and consequences of the Cold War. The causes of the Vietnam War revolve around the simple belief held by America that communism was threatening to expand all over south-east Asia.
The US got involved in the Vietnam War because it did not want another country going to communism (and therefore the Soviet sphere of influence) after what happened in China. (Also, check Tom Ray's comment on this one - frankly, he did a better j...