I will always love fantasy/fairytales above any other genre but I also read detective fiction, historical fiction, the odd thriller, some poetry and non-fiction (especially history and books like The Folklore of Discworld and Brewer's Dictionary of Phrase and Fable. The latter is perfect for dipping into and I can't think of a better way of finding out where favourite phrases come from). Favourite authors of mine include Jane Austen, P.G. Wodehouse, Terry Pratchett, Charles Dickens, Sir Arthur Conan Doyle and Agatha Christie. A nice mix I think!
One of my favourite non-fiction books is a slim volume called People of the Palace which looks at the role of royal servants over the centuries and how in some cases the roles have changed. I also read some wildlife books, Scrivener for Dummies has been really useful and I love books of letters too. Spike Milligan's Man of Letters is hilarious.
This is something I do love about writing. You get to improve your reading as well!