A poll conducted by the Performing Rights Society has found that the Doctor Who theme tune was the 3rd most recognisable one on British television. It lost out to the Match of the Day theme tune and then Eastenders, followed by Coronation Street and Countdown at 4th and 5th.
Despite doing so well, the recently revamped theme tune has caused some controversy amongst fans, claiming that the first half isn't actually that recognisable after all! Despite this, it is clearly a very popular piece of music, first composed by Ron Grainer in 1963.
Thanks to The Cloister Bell.net for this information!