I think it's mostly about getting the latino vote & nothing more than that.
he certainly could bring the “female vote” to the republican party.
I've seen an analysis showing that if the same percentage of Hispanics voted for McCain as for Bush then McCain would have been president.
The Rovian GOP establishment sees Rubio in the VP slot as the sure-fire way get back that enough Hispanics to win in 2012...or at least get Florida back in a pinch!