I pretty much have every railroad-oriented book, magazine, periodical, annual that I've ever acquired. Including quite a few from before I was born. I find it pretty fascinating to look at the ads from back then, or see 60 year old rolling stock being pitched as new. Storage hasn't been a problem, lugging it all has been... I actually have them reasonably organized, but many are in off-site storage. I don't regret hanging onto them, nor do I have any disposition plan I can live with. Cutting them isn't really an option - the effort would be monumental and as Denny pointed out, I'd be making future decisions in the present. Plus, one of the things I like most about the old magazines is the overall tone of them - in particular ads, product reviews, etc. that reflect the times and that's why I enjoy just grabbing a random 1956 MR from the dusty pile and reading it as if it's all new to me.
BTW, I love the musty smell. It's just a "train" smell to me - old magazines, basements, whatever.
Andy