If the slaves were never brought to the colonies of North America, how would that impact the current United States?

I don't know about you, but the United States would be a better place for sure.

We'd be pretty ****** if not for all the work they did

Without the slave cotton would be grown in India.

  Without the cotton  and cotton loom of the North our industries would be limited or slow to develop.

If the grown of industry was lowered roads and canal building would slowed or absent. 

The U.S. industrial revolution lowered, we may not have been able to confront the Spanish, never gained Asian territory, may have never built the Panama Canal.  May have never developed a Pacific Fleet, may never allied with China.  Japan may have gained it's 'Co-Prosperity Sphere'.  

... And America Government would have to entertain it's self with something other than world affairs. 

No jazz, no blues, no hip hop, no rap. Some other groups would have been assigned the low-paid, farm work, and would now be the underclass, committing crimes out of desperation and poverty. Economic development of the US would have been drastically slowed. 

Pretty much in the same manner as if, they had not be used in Nubia.

What's your point?

Well first, know that only about twelve percent of slaves were brought to the colonies of North America.  Most of them went to the Spanish colonies of South America. 

The United States would be safer and the standard of living would raise. Not to mention, the amount of crime would drastically decrease. The unemployment rate would decrease as well.