Here is some of their work:
KEITH HAIRNG
Keith Haring's art was inspired the graffiti in the New York City subways; the bold lines and colours.
Lori Nix says she was inspired by landscape painters. She was interested in looking at the city in a different perspective. The above picture shows a library taken over by nature in a future where mankind is no more.
Banksy was inspired by local artists in Bristol where he was brought up. His works are often based on satire and the message given is usually anti-war, anti-capitalist or anti-establishment.
Shepard Fairey has stated that he takes his influences and inspiration from other street artists along with films he has seen (such as John Carpenter's 'They Live'), and slogans/quotes from well known people (such as celebrities/philosophers etc.)
Barbara Kruger said that she was interested in the power of words/typography and how a few words could convey a large and hard-hitting message.