Just to respond to a post I missed in the last thread: I greatly prefer PDF's, but I will buy physical on occasion if it is an early release like 2SW at Origins, or occasionally if I really like the art in a book. I also tend to pick up a copy of core rulebooks, eventually, if I find them useful enough. For example, I've got physical copies of the AS rulebook and Companion, and TW/TO/TM, but I never really use SO or IO that much, so I only have them in PDF. I don't actually USE the physical copies all that much, but I keep them around as a sort of archive copy.
Beyond that, my collection is largely digital, and I prefer it that way.