I generally stick to fiction for my leisure reading, in part because of all of the textbooks I have to read for my college classes. Some of the books I have really enjoyed:

Dune by Frank Herbert (my favorite SF book)
A Place of Greater Safety by Hillary Mantel (an excellent historical fiction book set in the French Revolution)
Anything by Dorothy Sayers or Ellis Peters (mysteries)
The Pendragon cycle by Stephen R. Lawhead (a series set in Arthurian England)

There are plenty of others, but these are the ones that came to mind at the moment.