http://en.forums.wordpress.com/topic/how-to-remove-my-picture-in-profile?replies=10#post-110586
http://en.forums.wordpress.com/topic/pictures-in-rss-feed?replies=12
While we can choose to display or not other people's avatars on our blog, we don't have this option for our own avatar. (Uploading a "blank" white photo is still displaying a Profile Picture.) http://faq.wordpress.com/2008/06/19/new-avatar-options/
Apparently, this ability is important to some users. Thanks for listening.