Game: Agatha Christie: And Then There Were None

Rewind 10 years ago and it wasn't casual games that were all the rage among PC users - it was adventure games, where you play as the protagonist, walk around and talk with other characters for clues, collect items which you need to use to solve puzzles, and of course, unravel an interesting story as you progress throughout the game. My favorites were from LucasArts (Monkey Island, Full Throttle, Day of the Tentacle), Sierra (Gabriel Knight, Return to Zork, King's Quest) and of course the Myst games from Broderbund.