Which is it? a girlfriend or a friend? Because you don't give the same gift to both.
If its a friend, make it a gift that is special to her, something she likes. Listen to her talk about what she likes, or what she likes to do, and give her that.
If its a girlfriend, make it an intimate gift, such as a day together somewhere special, somewhere she likes to go.
DO NOT do the dinner and movie thing...its been played out, and no thought goes into it. Your girlfriend wants something you thought about and planned...the more thought and planning, the sweeter she will see your gift as.