One of the reasons why Inception was such a big hit was partly because of the music used during one of the trailers. Many thought the music had been created by Hans Zimmer, but in actual fact, it was done completely by one man, Zack Hemsey. Titled "Mind Heist", its an epic track, used to great effect. Even today, people think Hans Zimmer created it, but its all done by Zack Hemsey.
His music is so good, it has even been plagiarised by Steve Jablonsky during a key scene in Transformers Dark of The Moon, something which Hemsey addressed on his blog here.
SoundWorks Collection: Composer Zack Hemsey from Michael Coleman on Vimeo.
Zack Hemsey is actually a Hip Hop MC and composer extraordinaire. He started off composing for hip hop group called Nine Leaves where he is also an MC. His unique blend of electronic and orchestral gave Nine Leaves a very distinct sound.
Hemsey's first album contains Mind Heist and many other tracks which have been used in several more movie trailers. He doesn't actually compose for film, its actually Hollywood that has actively persued his music to be used.