The New York State legislature has mandated a little public health GIS. Pending Paterson's signature, the bill would require the state to map the incidence of cancer in an effort to find links between different cancers and their potential environmental causes. From the look (and talk) about it, the GIS will primarily be used to identify incidence hotspots. (The bill is twice talked about here and here.)
John Snow, you did good.
note: I exported the breast cancer incidence by county map from the National Cancer Institute, which allows you to both generate quick maps and download the datasets.