is there one? I read somewhere that they should look sort of like a quarter that is ovalish or elliptical, but isnt it different for each person?

Yes it is different for each person. Also it depends on what you have been eating too. Too little fiber will often cause small hard stools while plenty of fiber will give you a larger softer stool.

One more thing - What is considered "thin stools" ?

The reason I ask is because my stools are usually ovalish...as far as I remember have usually been this way. They are wider than they are thick