The primary importance of the Etruscans lies in their laying the foundations of Rome. The word "Rome" itself comes from an Etruscan word, which gives you some idea of how influential the Etruscans were on early Roman civilization.
In a relatively short period of time, the Etruscans were able to develop a thriving culture that spread throughout what is now central and Northern Italy. What made the Etruscans more advanced than other Italic peoples was their superior skill at mining metals, especially copper and iron, which gave them greater wealth and military power than their rivals. The Romans themselves would be renowned for their mining, and it's not difficult to see the influence here of their Etruscan forebears.
The Etruscans used their superior governing abilities to organize what was then a loose collection of farming communities into the full-blown city-state of Rome. Their ruling elite provided Rome with the main components of its political system: a government and an army. It's no accident that the few Etruscan words that entered the Latin language were related to the power of the state. One such word is fasces, the bundle of whipping-rods carried around by magistrates' attendants which symbolized their authority.