Current Obsession Round Sunglasses

I am currently obbessed with round sunglasses and I don't know why.  Ever since they started to have more vareity I have been hooked.  I love the round ones from Prada and the half tint ones the most.  The girl in the third last picture is adorable she is so over the top it works at least in my opinion bag lady chic strikes again.  

What are your favorite and least favorite style of sunglasses?