Upstate New York Genealogy Blog has posted an entry on "Accessing New York State Vital Records," with some commentary about the locations of microfiche indexes to these records, which start in the late 1800s.
I've put off getting vitals on my wife's Clinton County, New York, relatives but might start now--particularly Louis Demar who lived in New York state for several years, moved to Chicago for approximately twenty years and apparently returned to Clinton County after the 1930 census.