The USA had 6 consecutive presidential elections (1928-1948) with at least one New Yorker on a major ticket and 2 (1940 and 1944) with two New Yorkers running against each other. Since then no New Yorkers have been nominated by either the democrats or republicans. How many could have become president since FDR?
To start off with, there's Thomas Dewey, the final nominee, who easily could have won in 1948 but ran a lackluster campaign.
There's also the oft-mentioned Nelson Rockefeller, who could have won the Republican nomination in 1960 with the right POD. Also, he served as Ford's VP and would have briefly become president if Ford had died in office.
Mario Cuomo was a popular choice for the democrats after 1988, but he ruled himself out before the '92 primaries due to Bush's popularity.