This Families USA report estimates that 275,000 adults will die prematurely between 2010 and 2019 if Congress fails to enact health care reform.  The report provides state-level data, predicting that California, Texas, Florida, New York, Georgia, and North Carolina will be among the most affected. 

From the introduction:

In 1994, when health reform was last debated, the number of uninsured Americans was nearly 40 million. Today, that number has risen to nearly 50 million. For these uninsured Americans, going without health coverage can have serious consequences. We know that the uninsured are too often burdened by medical debt, they delay care until their health problems grow severe and the cost of treatment escalates, and they often go without any care at all. And worst of all, people who lack coverage may die prematurely.

In 2002, the Institute of Medicine issued a groundbreaking report, Care without Coverage: Too Little, Too Late, which estimated that, nationwide, 18,000 adults between the ages of 25 and 64 died in 2000 because they did not have health insurance. Subsequently, The Urban Institute updated that figure, estimating that, in 2006, at least 22,000 adults in the same age group died because they did not have health insurance.

Full report: Lives on the Line of the Deadly Consequences of Delaying Health Reform (PDF | 343 KB) 

Families USA. (2010) Lives on the line the deadly consequences of delaying health reform.