Most girls know that trumpet players are where it's at.
No, I've got to say, there are definitely a slice of women who swoon at the sight of a guy with a guitar, especially if he knows what he's doing with it. I remember back in college (in the first week of freshman year, before lurkette and I were official), I led a sing-along with my guitar in the stairwell of our dorm, on a girls' floor (lurkette's floor, in fact), and I must have had eight to ten girls clustered around singing with me. I got some very interested looks that night. Which was all very good fun, but I had already picked my pony.