git diff --name-only | uniq | xargs subl
I found it useful to create an alias too:
git config --global alias.mc \ '!sh -c "git diff --name-only | uniq | xargs subl"'
And of course you can substitute subl for your favorite editor.
Life can be much broader once you discover one simple fact: everything around that you call life, was made up by people no smarter than you.