If you go, I would try to get a guided tour of the treasury. The other rooms can be nice enough to have a guided tour of, but the treasury is minimal in information, so the guided tour is almost essential in order for there to be a point of walking down all the stairs to get there. Well, beyond – glitter and gold, that is!
I actually think that the Three Crowns museum beneath the palace was my favorite bit. Maybe because my main interest in royalty is actually the history of it all.
Nitpick: I’m not sure if this is just because the ticket building (outside the main palace) was being renovated, but it seemed like there was a charge to use the bathrooms in that building. When I’m being charged £14 for visiting a tourist attraction, it does rather feel to me like that should include free access to the toilets in the ticket building.
I was surprised by how prominent the Palace really stands in the city. It seemed like whenever I turned a corner, there it was again. It is much bigger than what I’d thought in advance.