Gallup asked people whether they would vote for a presidential candidate their party nominated who was generally well-qualified to be president but had various characteristics.  Here they are with the percentage of respondents saying yes to each (I've also added the relevant politicians in each category):

Black: 94% (Barack Obama) (1)
Woman: 88% (Hillary Clinton) (2)
Mormon: 72% (Mitt Romney)
Married 3 times: 67% (Rudy Giuliani)
72+ years old: 57% (John McCain)

1 Gallup head Frank Newport argues that there's really no discrepancy anymore in how black candidates fare in pre-election polls vs. at the ballot box.

2 Gallup speculates that this figure may be artificially low because Republicans instinctively think of Hillary even though she's not in the question.

Note that these results would seem to favor Democrats in 2008.  :D