I'm with BP on this one.
Generally I reserve a 5 rating for something that offers a lot of benefit to a lot of the community (i.e. Jmdt's ttw study) and a 1 for something that's either broadly offensive or otherwise should not have been posted.
However, I haven't seen any guidlines anywhere as to how we're supposed to use the rating system, so I guess it's largely up to the individual.
As a general rule, rating systems should only be used to rate your opinion of the game. Not a weighted opinion (aka it has a 1 you think it deserves a 3, and so you give a 5) as this doesnt truely show the community view of the topic.
For ex
A game has (5) 1 star ratings and nothing else. Avg Score=1 Star
I think the people are too harsh, and while my opinion is only that it deserves 3 stars, I give it 5.
That means the game now has (5) 1 star ratings and (1) 5 star rating. Avg Score=1.666 Star
Meanwhile, you should give it 3 stars since thats what you think it deserves.
That would mean it has (5) 1 star ratings and (1) 3 star rating. Avg Score=1.333
the goal of the ating system is to see what the community as a whole (or at least those that rated it) thinks of the topic. If you give a higher than what you think opinion, then the true rating of a topic isnt really known.
Guidelines like these should be made.