The xmp files don’t bother me because I’m basically never viewing the photos in the computer folders, I do ALL my organizing, viewing, editing, etc in Lightroom. As far as organizing photos, I follow the workflow laid out in the lesson, Secrets to Organizing Photos, in the Foundations Course. That has worked great for me. Besides things mentioned in that lesson, another way to save space is to delete photos. 🙂 Personally I don’t actually delete a TON of photos, but if they’re remarkably bad I’ll reject flag them in Lightroom and then every so often I delete all the reject-flagged photos.