Another way to figure out what you like is to look at what you enjoy as guilty pleasures. Many things people like, especially if they're young and ambitious, they like largely for the feeling of virtue in liking them. 99% of people reading Ulysses are thinking "I'm reading Ulysses" as they do it. A guilty pleasure is at least a pure one. What do you read when you don't feel up to being virtuous? What kind of book do you read and feel sad that there's only half of it left, instead of being impressed that you're half way through? That's what you really like.
So, what are your guilty pleasures? What kind of novels do you pick up for comfort reading? I know someone with the complete works of Dick Francis, who'll happily re-read them over and over again. Me, I'm addicted to John Irving's The World According to Garp, and All the President's Men by Woodward and Bernstein. Stephen King's On Writing lives in the bathroom. Among graphic novels I'll happy savour Watchmen anytime - but always skip over the Tales of the Black Freighter sequences.