My favorite game of all time is Indiana Jones and the Fate of Atlantis. I love The Secret of Monkey Island and Loom almost as much, but I think that Indy is the best of the three, objectively. (longer than Loom, and without the boring parts and sometimes illogical puzzles of MI)
And then Grim Fandango, DOTT, MI2, and The Dig are an inch behind. With Sam and Max, of course.