Instruments are in a vast amount. Nevertheless, not all of them are that cool for the musicians.

Personally, I think that the  coolest musical instruments are the electric guitar, acustic guitar and the drums.

Additionally, the guitars are the ones that give the rhythm to the song. The electric guitar produces that amazing sound all over the solos, which also helps the song become larger.

On the other hand, the bass guitar, piano and the rest of the musical instruments do not compare to what the guitar is.

The drums are the ones that help to follow an specific time along the song, indicating the changes of  the voices and pauses, so that the song would have an order as well.

To summarize, all instruments could have an important part in the song, but which would give to the song the needed ingredients are the guitars and Drums.