The Qin introduced uniformity of measurements, script, and monetization of the economy. The highly meritocratic (as opposed to nobility by birth) society encourages of professionalism. The Qin also fans national identity through national service, promulgation of law and order, tax reforms, management of unemployment, and creation of passports.
In the state of Qin, salary and taxes are paid in cash, and nobody (including royalty) is exempted from law and order. The government is the only body that mints coins so well made so much so that forgeries are scarce. The king creates employment by giving farm land to every nucleus household and collects surprisingly reasonable tax from the produce.
The Qin places importance in urban planning, massive construction of road ways (highways) and waterways, both so sophisticated, that are still in use today. There is a highway leading from its capital Xianyang all the way to today's Inner Mongolia, and even one that stretches all the way to Nanhai (today's Guangdong).
They also built massive irrigation system, greatly improving agricultural cultivation. Again, the same irrigation network built by the Qin is still in use today.
Such a magnificent kingdom, the initiator of the Qin Dynasty, unifier of warring states. A kingdom of technological advancements, intellectual ideas, and effective governance.... yet too short lived.
Merely four years after the death of Qin Shih Huangdi (First Emperor of Qin), the Qin collapsed.
It leaves behind only blue print of effective and modern public policy for a land as big as China.
Well, and perhaps, the impressive terracotta warriors and mystery surrounding it :)