To me, a bag has to be comfortable and light enough to be carried around. It is pointless to carry an extremely gorgeous bag but it is uncomfortable and feel like a chore to lug it around..
I have the SO-ed Galliera in Damier Ebene, Romance Idylle in Fusain and Monty. They are pretty light in comparison with the other models.
However, the Monty is the lightest, followed by Romance Idylle and Galliera.