It is the instrument that can capture the person's imagination, and which will give easy rewards in those first few weeks, and then present challenges when the young musician is genuinely hooked.

With me, it was the harmonica. It is easy to pick out a few tunes by ear, so that you have something to play in between "serious" practising.

At the other end of the scale would be something like the violin or trombone where it can take weeks simply to produce a decent note in tune.

The guitar is perhaps the most versatile, and has the advantage of being suitable for almost every genre of music, from folk to country to rock and roll to heavy rock to classical.

It helps if there are obvious role models and plenty of inspiring stuff to listen to. (My own problem here is that most harmonica that you I is blues and country style (bending the notes, playing on the draw and so on) or, if "straight", played on tremelo tuned instruments.)