I would nest my bags as much as possible, like matryoshkas, to maximize space haha! SLGs would fill in crevices. I think if I did this, I could fit almost everything...but if I couldn't, most of my Massaccesis would be packed first (hoping his Kickstarter campaign that just launched is successful!), then Henri Bendel (since HB has closed), and the rest in order of sentimentality haha...Speaking of packing up and moving to a new city, what would you take with you if you had to fit your bag collection into the back of your car (not a U-Haul haha), or even into two luggages for a plane ride? Could you downsize, and if you could, what's keeping you from getting rid of all the bags you'd leave behind now?
For the most part I sell or give away what I don't use; some bags like totes I could downsize but even cheap ones are becoming increasingly useful as cities charge for grocery bags and kids needing more stuff to log around for various activities...