In fact, up until Bush-Kerry, I recall a story about taller candidates consistently winning the last 12 election cycles. I'll have to google for that story...
ETA: From Cecil's Adam's "The Straight Dope"
That caveat aside, various sources do claim that the taller candidate usually wins. For example, in Language on Vacation (1965), word and number buff Dmitri Borgmann claimed that in the 19 U.S. presidential elections between 1888 and 1960, the taller candidate won the popular vote all but once, when 6'2" Franklin Roosevelt beat 6'2-1/2" Wendell Willkie in 1940. In 1888 5'11" Grover Cleveland beat 5'6" Benjamin Harrison at the polls but was cuffed in the electoral college, and in 1896 and 1900 both candidates were the same height.
In his 1982 book Too Small, Too Tall psychologist John Gillis presents similar results: in the 21 presidential elections from 1904 to 1984, the taller candidate won 80 percent of the time. What's more, he says, in the whole history of the Republic, only two presidents--Harrison and James Madison (5'4")--were appreciably shorter than the average height in their day"
http://www.straightdope.com/columns/read/787/does-the-taller-candidate-always-win-the-election