Out of the instruments that are usable for both melody/soloing and harmony/accompaniment, the guitar family has the clinching virtues of being cheap and portable. Like keyboard instruments it is also applicable to virtually any genre of music. K/b instruments are more suited to complex material (hence their use in composition), whereas the guitar family allows more expression than instruments that are essentially controlled by switches.

These advantages entail one overriding disadvantage: ever other bugger plays one. So it is proportionally harder to get into a band or college. If you want gigs,play something cumbersome, like drums, double bass or euphonium.