Executive Summary: Do not use Creative Commons at all if you want to retain all rights to your work. Creative Commons always means giving up some part of your copyright.
And now the long story. Actually, there's other stuff I want to say, including a lengthy feature session that I just can't get the energy to write, but this one has been nagging at me since forever. Many artists here take their copyright seriously, but a large subset of them then goes and does something completely unhelpful thanks to a lack of information. Just now, I've read a news post titled "Protect Your Work, COPYRIGHT YOURSELF.". The title makes no sense at all and the actual text only gets worse - hence my not linking to it. So I thought I'd clear up some common issues.
Copyright by default
If you just put your picture up here and absolutely ignore the "Creative Commons" section of the upload form, then you get full copyright protection. You don't have to put a © Myself 20