Anti-hero Heroes and Anti-villain Villains?

I've spoken before about my desire to see/write more ambiguous villains. Maybe ambiguous is not the right word. But although I read or watch a story about the Big Bad (Voldemort, The Emperor from the Fables comics, Ma'ar and his incarnations in the Valdemar/Velgarath books), and greatly enjoy--can't wait for the next Valdemar book--when I am writing a story, I like to play with the idea of what's "evil".

Some books can have the flat-out evil villain whose only goal is world domination for the sake of world domination, and there are flat-out evil villains who want world domination for some other reason, but I like to work on a small scale, and play with the villains who have reasons for what they do and don't necessarily see themselves as a villain. Where even the hero or the reader wouldn't always call them a villain.

Shades of grey...if you can have heroes who are not particularly heroic, or don't want to be anyway, and who may have issues with morality, why can't the reverse be true as well?

Bookview Cafe, a site that brings together the thoughts and opinions of a number of authors, included a recent post that talked about some of the same ideas. by Sherwood Smith looks at the central conflict of heroes and villains, and the discussion that follows includes a bonus!Avatar: The Last Airbender comment.

There is also an earlier Bookview post by Smith that starts off this conversation.

"Villains are the heroes of their own stories."
What do you think?