Waking up early in the morning on that first full day, going out to the balcony and taking in the view, knowing that I have a wonderful magical week ahead of me. Sitting at the busstop waiting for that first bus to whereever.
For me it's the first sighting of the Castle at Mk from the bus. Our first trip was when dd was 8. She had no clue what WDW would be like. She thought it would be similar to the local 6 flags, lol! The look on her face on the first trip when the Castle first came into view was priceless. She is now 22 and she still gets "that look" when we approach the MK and see the Castle.