Periodically I do a clearance and set things aside to sell on ebay or craigslist... It really isn't that bad for the money you get. Just take a picture of everything and ebay has software called turbo lister that lets you create listings offline, and you can just duplicate listings, etc.

That being said, I've got a box full of stuff I've been procrastinating on.

As for clutter... I have a tendancy to clutter. It makes me feel better making sure that i have a certain number of rooms clutter free - so my upstairs I try to keep clutter free, and I can make all the mess I want downstairs...

I did recently buy a huge filing cabinet off craigslist... all my papers are currently in there, but I cannot claim that they are in any sort of order. that is for another time.