He's much shorter than Obama. Obama is about six foot one, McCain five foot six. Starting with Hoover in 1928, arguably the election nearest the start of the Movietone News and then TV era, the taller candidate has won 16 of the 20 elections, or
80%. Interestingly, W is one of the three Presidents to buck the trend, in both his elections (the other two are Carter and Nixon. Hmmm. Carter, Nixon, W. You might think those who can buck the natural trend would be particularly impressive, but obviously not). Still, Kerry was so tall (six foot four) that his height made him look a bit dorky and, disastrously, aristocratic and "French"; and Bush didn't actually beat Gore, did he?
More details in
this oddly charming Wikipedia article.