In my opinion, 'The Hellbound Heart' is one of the best Clive Barker stories. It introduced the Cenobites in a really fascinating way. The concept of a puzzle box that unlocks a dimension of extreme pain and pleasure is both terrifying and thought - provoking.
I think 'Books of Blood' contains some of his best work. There are so many different stories in there, each with its own unique brand of horror. Barker's ability to create vivid and disturbing images really shines through in these stories, and they cover a wide range of themes from the psychological to the supernatural.