Unlike another of my friends (Greg), I can't say I've been a Doctor Who fan since the beginning. Honestly, I have had a hard time watching some of the older incarnations.
However, I have always thought that the title theme was iconic. If there has ever been an example of how music almost becomes another character in these little screenplays, this is it. The following is a compilation of how things have evolved over the years. With slight adjustments for the styles of the day, it has remained fairly constant. And why not? If it's not broken, why fix it?