The Qin Dynasty is referred to as the "first" dynasty not because of its role as a ruling power, but because Qin Shi Huangdi instituted the framework for the imperial bureaucracy that China would have for nearly 2000 years after. The dynasties you list above (of which one, the Xia, we aren't sure actually existed as a separate entity) were more like kingdoms with feudal vassals that made no attempt to centralize power.

The hammy acting in the dramatizations aside, this documentary does a fairly decent job explaining the significance of the imperial bureaucratic system (jump to about 55 minutes in). Whereas before rulers relied on local authorities for administration, Qin systematically reorganized administrative units and local counties, instituting a common code of laws. Instead of relying on nepotism to staff positions, Qin encouraged the development of military, legal, and political professionals to fill local positions. Since this system long outlasted the Qin Dynasty, it's considered, both historically and culturally, the foundation of imperial china.

For more information, check out these books:

• Michael Loewe, The Government of the Qin and Han Empires: 221 BCE—220 CE (2006).
• Charles Sanfit, [Communication and Cooperation in Early Imperial China: Publicizing the Qin Dynasty] (http://books.google.com/books?id=BOhTAgAAQBAJ&printsec=frontcover&dq=qin+dynasty&hl=en&sa=X&ei=XH1eU9ClHNSvyASouYLwAw&sqi=2&ved=0CDkQ6AEwAw#v=onepage&q=qin%20dynasty&f=false) (2014).
• Milton Walter Meyer, China: A Concise History (2nd Ed., 1994), esp. chapter 11.
• R. P. Peerenboom, Law and Morality in Ancient China: The Silk Manuscripts of Huang-Lao (1993).

Always room for more discussion, but FYI a similar question was asked yesterday