well, I am all for downsizing stuff and making room...esp. for more fabric, lol...but since I am a person that might come back later and really like something that i didn't pay any particular attention to before...maybe I wasn't ready for that level of skill yet, etc. here's what I do to help myself with my magazines:
I put one of those 5x7 post its on the cover, with the patterns, etc. that I am most sure i will want to consider in the future.
I always take mags or books to appointments so I usually pic a magazine that has a long list on the post it, so I know I am going to have a good time remembering those, "oh yeah, I gotta make this one someday, for sure", patterns. :-)