I have been thrilled with freecycle.org, though. I find usable stuff I want to get rid of, post it on my area loop, and there is someone who wants it. They come pick it up too! I just leave it on my doorstep.
Oh - every time we've had a garage sale we've been stunned at how much our junk added up to! But you can't only choose to sell stuff that is worthless... gotta put some bigger ticket items out there.