Girls like Glee and guys like Slayer. Check out last.fm's data visualization on what people listen to, broken down by gender.
The last.fm blog put together this interesting look at what music people on the site are listening to, broken down by gender (large version here). On the bottom of this list are the artists that are popular with women. On the top, the artists the guys like. The x axis is age.
For the most part, it's pretty unsurprising. The Beatles, Radiohead, and the Red Hot Chili Peppers appeal to men and women equally. Ladies like the music from Glee and guys like Slayer.
What's interesting, though, is the fact that the gender specificity of music tends to fade away with age. There's not a lot of music that appeals to older women, but not older men, or vice versa. That bodes well for harmony between the sexes, right?