During our recent move into our new home, I got rid of a loooooottt of crap. It's frightening how much useless junk you can accumulate over a short time. As a result I've cut down on a lot of impulse spending and our house is less cluttered.
That being said, I still hold on to my books (comics and otherwise), photos, paintings, and a few trinkets that hold personal meaning. @mmikaoj has some good points, but for those of us who are a little more settled, it's nice to have those pieces of our past to reflect on. Having things isn't just about consumerism, it's about being able to touch your past and revel in the associated emotions and memories.
Sure, none of it is coming with us when we die, but at that point my son will get to enjoy my dog eared "The Tick" comics.