English Heritage has been asking its members for its top 10 castles. The list consists of: Dover, Kenilworth, Tintagel, Bolsover, Portchester, Warkworth, Dunstanburgh, Carisbrooke, Middleham and Beeston.
Many of these would be in my personal top 10 English Heritage castles especially Bolsover. But what would I want to include? Leaving aside the artillery forts like Pendennis and Tilbury, I would want to consider:
One of the most dramatic castles is Peveril standing above the Derbyshire village of Castleton famous for its Blue John mines.
Scarborough Castle has dramatic views over the bays on each side. It also contains a Roman signal station.
Brougham Castle lies on the site of a Roman fort on the Roman road that crossed the Pennines.
Farnham Castle dominates the town.
Castle Rising has a wonderful keep standing within earthworks.
Orford provides magnificent views over the Suffolk coast.
Hadleigh Castle provides dramatic views over the Thames estuary.
Helmsley Castle lies on the edge of the Yorkshire market town.
Heritage Futures 
Thats a fine selection, I particularly like your photo of CASTLE RISING which (from archaeology) is thought to be similar to the castle which existed in Castle Cary, sadly destroyed in the 12thC. We now have a model of Cary Castle in our Museum which clearly demonstrates its situation in the landscape. For anyone visiting Somerset, there is an excellent exhibition CARY 21, a history of Castle Cary in 21 objects, open until 5th September. (note, the Museum itself is currently closed but the Special Exhibition is OPEN in the same building, the historic Market House).
Thank you for drawing attention to the exhibition. I wanted to put Nunney Castle in the list as a gem of a castle.