Watchmaker
Fans of traditional adventure games will enjoy the puzzles and will likely be able to bear with the awful voice acting and the underdeveloped story.
Runaway: A Road Adventure
It has pretty much everything you'd want out of a solid adventure gaming experience.
Broken Sword: The Sleepi
Developer Revolution Software really understands the adventure genre and capitalizes on its strengths in Broken Sword: The Sleeping Dragon.