dude, my advise... if u can write her a song !! and play it for her, it could be watever instument you wana play.

If not, go find meaningful songs or songs that make ur gf think of you'll and burn into a cd, make a really really nice album cover and put in all the details like bar codes, price, producer...etc...etc.. it will be your love compliation cd !

cheers mate good luck.