I've changed my rating system a few times. I've found though that using stars, 1 being the worst, and 5 being the best is the best system to use.
My rating system:
|Stupendous! Add to your To Be Read List right away!|
|A great book! Definitely add it to your To Be Read list!|
|A good book. Add it to your To Be Read List, and eventually get to it.|
|An okay book. Might be worth adding to your To Be Read list.|
|Horrible book. I do not suggest it to anyone!|