Book space is a biggie for us too @Determined. We've been running on "not enough bookcases" for a long time. Obtained a couple more just recently. There's also a "too many books" issue, but the thing is that if we can put them in bookcases, we can see what's there clearly enough to cull, so it's a bit of a circular issue.
We've also got a lot of magazines, but we don't buy the throwaway ones. We get the specialist craft and art magazines, or the practical skills ones. The sort that are actually still of real use 10 years on from their publication date. So most of those also merit bookshelf space.
I've got the same issue at my parents' house. Any "New Idea" style magazines have gone straight in the recycling, but I want to try to find new owners for the special interest magazines. I know someone who will be keenly interested in Mum's smocking magazines, because they're no longer available new, and rarely as backissues. For other ones, we're thinking along the lines of a "pop up bookshop" on our driveway, but not sure if we'll be sorted enough to do it this year, or next year. Or maybe we can manage both. There's a big weekend event that happens in our town every autumn that would be the ideal time to move them on.
Current de-clutter project is a desk that's moving in to our daughter's room so that she'll have a decent space for doing high school homework. The books (and magazines...) that were on top of it are easy enough- into the bookshelves with them! The boxful of assorted unrelated oddments is a bit more challenging.