Do you think that some non recumbent stone circles reflect the landscapes around them? On a recent visit to Castlerigg, I thought it was clear that the stones matched up with the hills and valleys around it?
You should get hold of a copy Richard Bradley's 'The Significance of Monuments'. I think it will answer many of your questions regarding henges & circles and a whole lot more besides. It's all far too clever for me to summarise here but I would recommend it to anyone who wants to delve into this area.