There have been some topics about this in the past on RPGamer forums, but it has been awhile since the last one.
What are your favorite and/or least favorite RPG cliches? Which ones are horribly overused to the point of no return?
If you haven't checked it yet, there's a huge list of cliches over at TV Tropes. There is no separate category for RPG-specific tropes (only videogames).
Save the world is horribly, terribly overused. When I'm done saving the world, it just gets itself back in jeopardy again!