I scan my 6x7 slides as projectors for this size are way over my budget. I also scan my print film negs, as I'm still trying to decide which format to stick with, although it looks like print film will win in the end when I eventually get round to start processing colour. If I want a print of a particularly good pic though, I take the file to a local lab and get a 16x12 done.
Going back to the post about deterioration of slides, my father's 6x6 slides from the 60s and 70s were dug out when I bought my Epsom v700 in order to scan them. Most of them were still spot-on despite being in buried among junk up in the loft for 30 years, but some had acquired a strong magenta cast, which I had to remove digitally. As the deteriorated slides were the same age as the good ones, it must have been the quality of film used at the time. Not all the slides have the film make on them, but the good ones seem to be Agfa colour, whereas the pinky ones were Gavaert, whoever they were. Anybody heard of them?
I remember our family slide shows, and as someone has already said, its the magic of a beam of light in a darkened room which computer screens can never equal. We still have our old 6x6 projector, (probably in the loft too) so reading this thread has started me thinking about shooting a roll of 6x6 on my Yashica Mat just to crank the old magic lantern up again. If it works....