I agree about movie nights! It's always fun to watch them as a family. The Disney World DVD will definitely help her with what she will see once she is there.
We've done two surprises. One was for our son's 2nd birthday where we wrapped a box with t-shirts, some Disney pens/grow towels/autograph books, along with a Disney for Kids book with helium balloons on top. When our son opened the box, out came the balloons with an invitation to come to Disney from Mickey attached. Our oldest son was so excited, and that made our youngest son excited. The best part was that we were leaving the next day, so there was really no waiting for our trip.
The second time was at Christmas and we had a scavenger hunt. The clues brought them back to a gift under our tree that had Disney stuff in it for both boys, along with a countdown calendar. They were both thrilled....and to top it off we told them my parents were coming with us which made it even more magical!