A neat-o graph:
Essentially, the life expentancy rises in an almost lineal fashion with health care spending. Except for the United States, which is the outlier.
Some of the debate is here. There is some debate as to whether life expectancy is a good measure of things, that this comment rebuts rather neatly:
Certainly life expectancy isn't a perfect measure of a country's health care system, but saying that it shouldn't be used as a measure is like saying a sports team's win-loss record doesn't reflect the team's talent. At the end of the day all of the other statistics are meaningless if we come up short in the ultimate measure of success (in this case life expectancy).
I agree with you that other factors are involved, but why wouldn't obesity and teenage pregnancy be considered aspects of a country's health care system. A health care system should promote a healthy lifestyle, not just save us from an unhealhty one.