Anton Zykin, a professional icon designer from softfacade icons has agreed to design a suite of icons for d7 and release them under the GPL license agreement - for free. When Anton and I first talked, I believe I framed the discussion as 20 icons. That said, recognizing that we can easily go over 20, we need to keep the initiative to a core set.
I've scoured the issues and arrived at the list of icons. I've used a scale of 1-5000 to help us identify a priority and sort: