Some good murder mysteries, where you try to figure out the murderer. A whodunit.

I'm looking for suggestions for a good mystery novel that has a cast of characters, and you try to piece the clues together to figure out the culprit. I've recently read the Westing Game, which I enjoyed but didn't love. I've read a few Agatha Christies many years ago, which were great, and happy to hear suggestions for particular Agatha Christie novels (I can't remember which ones I read).