I get asked this question a lot, and the answer depends on my mood, current preoccupations, or authors I might be reading. One thing I tend to go for are people who are amusing. Right now I'd go for author Alexis Hall, actor Matthew Goode, and actress Dame Judy Dench. Ask me tomorrow and I might give you a different answer.
So many possibilities. Persuasion by Jane Austen for a romance classic. Gaudy Night by Dorothy L. Sayers for the perfect academic novel. The Girl He Used to Know, which for me is a great modern novel. Almost anything by Agatha Christie for the perfect puzzle mystery.