I replay most of my games at least once. I've played Sherlock Holmes: The Case of the Silver Earring 4 times now. I'm just starting to get the hang of those wretched quizzes at the end of each chapter - practice makes perfect.
Black Mirror and Dracula Resurrection are another couple of favourites (3 times each), and I'm thinking of replaying Still Life for the 3rd time over the Christmas holidays. Yeah, it will happen.
These games carry a feelgood vibe for me, it's a pleasure to revisit them all.