Probably my favorite movie is Highlander from 1986. When planning a trip to Scotland, I had to make sure the Eilean Donan Castle was on the agenda. To me this castle is the epitome of what a castle should be. Situated on a tidal island with a clear 360ยบ field of view. It has also been a functional castle over the years. I enjoyed the tour which is really good featuring armaments, stairs and secret passages.
If you are driving to Skye, it is a short detour from Kyle of Lochalsh bridge that connects Skye to the main part of Scotland. It is a worthwhile stop. It takes about 2 hours to wander around the castle if you follow the audio tour. Be sure to check the tide schedule in addition to the weather forecast. At high tide, the castle is surrounded by water. At low tide, you can see the exposed flats and rocks. I would not recommend walking on the flats but at least they are not dangerous like in Anchorage.
This castle has also appeared in James Bond film, The World is Not Enough, as MI6 Headquarters Scotland, and the movies Elizabeth: The Golden Age, Entrapment, and Rob Roy, to name a few. In the movie Highlander they talk about this castle as the home of Clan Macleod (actually Clan MacRae) and how they had to cover the parking lot with dirt for the shoot.