I would keep some mementoes (like one of your wedding favours, a travel mug or two, your cake topper, etc.). I have a dress box that I put a few other mementoes in and although I still have my dress, I'm not emotionally attached to it and may sell or donate it. I think the important thing is to let go of the decorative stuff, as you probably have plenty of plenty of pictures of the decor and you don't need it clogging up your space.