The Fourth Doctor Doctor Who theme music is eternally beautiful to me. I've always been absolutely mesmerized by that haunting swirl of music accompanied by its simple but masterful visual effects.
Today, the theme continues to amaze as it did when the series returned in 2005. English composer Murray Gold [1969-present] stayed faithful to the classic sound [originally composed by Ron Grainer] while reinvigorating that thrilling theme by offering a modified arrangement. He clearly approached the series as a musical director in much the same way Russell T. Davies handled Doctor Who itself.
Gold also penned themes for Doctor Who associates, The Sarah Jane Adventures and Torchwood. Gold continues to serve as Doctor Who musical director and can be spotted in a cameo in Voyage Of The Damned  featuring the ever beautiful and sexy Kylie Minogue.