One thing that I would suggest for senitmental items that you want to keep, is to scan them. We recently had a fire in our house and lost everything. I had been meaning to scan in all the papers my mom had saved from my baby years, but hadn't gotten around to it yet. Scan them in and send a cooy of the files to a friend or relative. For those bigger items that you want to keep a memory of, but don't necassarily want to keep the item around, take a picture. I did this when I was getting married and it saved so much on packing stuff up and moving it. Again, make a copy of the pictures and send them somewhere else.
It takes time, but in an emergency, you'll be truly grateful. You will still have the memories, even if for some reason you get rid of the actual item. And a couple CDs are easier to deal with than boxes of stuff.