You Can Vote For McCain, Or You Can Keep Your Health Insurance...

...but under his plan, it's unlikely that you can do both:

But this is the main fact worth knowing, and repeating, about John McCain's health care plan: Its first-order effect would be to take employer health insurance away from 20 million Americans who currently have it. And this estimate is on the low-end. The authors write that it only looks at what employers would do in response to the new tax rules. It does not examine "the number of low-wage workers who might lose employer-sponsored insurance when employers are no longer bound by the nondiscrimination rules, nor do they capture the impact of breaking up existing risk pools." In other words, 20 million plus will lose their employer-based health insurance.

(The bold, and some of the italics, are mine.)

Further details available here.