Dunstanburgh Castle on the Northumberland coast looks windswept and interesting (it even forms the backdrop to one of my stories), but in its day it was as bloody and murderous as any fortress in Game of Thrones.
In the debateable lands of the north, the murderous lords and princes of that time really were playing a Game of Thrones, and Dunstanburgh, built by House Lancaster as a refuge in their dispute with the King but often in the hands of their rivals the House of York (GOT fans, think House Lannister/Stark), was finally reduced to rubble by cannon.
The Northumberland coast is scattered with castles, some ruined, some restored, some still glorious. Between those monuments to a time of war, and the endless beaches, this coastline is my favourite place.