The first thing I tend to notice, over general physical attributions, is a girl's eyes. Usually because you can tell so much from just one tiny look, and personality is the most thing me. But on the physical side, my perfect girl would be about 5 ft 7. However, anything between 5 ft 3 to 6 ft is fine.
Well, qualities like these have to come in moderation due to our human need of contrast. However, I do prefer girly to sporty, even though I myself try to stay active. My ideal girlfriend would of course join me in such activities. It's easy to love a girl with a great laugh, but as mentioned before, too much and it loses all meaning. Girls who are clumsy tend to be really cute to us with a nurturing side. Hug.
I really don't care too much about the physical attributes, such as weight, height or general look. But some features, such as the eyes and smile, are important to me. The girl of my dreams must have a somewhat silly side that enjoys the mutual teasing. I don't care too much about smarts as in facts, but she would need a state of awareness about the world. Politics, philosophy- that's is more or less a requirement.
On a personal level, I would not find it attractive if she would be able to play an instrument. But that mostly due to my own lack of musical talent. Though, I probably would if I even so only had a decent singing voice, so we could enjoy her gift together. Most guys search for someone to take their mother's place, but seeing as I'm more of the nurturing type myself, my desire is probably lower than most.