Depends how much sex appeal is involved. For example, it didn't matter so much to me with Mass Effect. Sure, Miranda, Samara, and Jack made me feel a little uncomfortable, but I just laughed at how horribly impractical their outfits were, what with the jumpsuit wedgies, questionable dress codes of grandma space nuns, and imaginary "Oh dear lord subzero temperatures of outer space are COLD why am I running around without a shirt?!" monologues.
But when they go too far, they interfere with my ability to play. And there's no point in buying a game I cannot play effectively. As a straight female, I can't enjoy jiggles physics as much as some guys do. (So yes, it can decide what games I buy. If there's a lot of it, I won't buy it.)