Take her on a surprise trip somewhere a few hours away. Try to make it for the entire weekend. Take her to eat at a nice restaurant and after they have cleared the plates from the table and the waiter/waitress comes to see if you need anything else, hand her/him a camera and ask that they take a picture of the two of you together. As the waiter/waitress goes to take the picture get down on one knee and propose. You now have pictures to remember the day forever.