Just a month ago, we actually made a huge donation of all sorts of computers, electronics, and other items to a group called Urban Renewal Corp. (urbanrenewal.org) in New Jersey. They seem to be doing some really great work helping and educating the homeless and others in need.
They also recycle or find ways to reuse everything that's donated, which is great all around because even stuff that may ordinarily end up in landfills, they can find others ways to re-purpose it.
Plus, as you said, you are also eligible for a tax deduction, and it all goes towards a great cause as well!