Great job on the plugin. I'm using it live on my site here. There are 2 features that I'd like to request.
1. Pinterest sharing. Seems pretty popular at the moment, especially among females and photographers.
2. Bit.ly support for Twitter. You've got to admit it, sometimes when sharing a lengthy link on Twitter it becomes imperative to use a 3rd party shrinking service. You might check the code in the WP to Twitter plugin for some ideas on coding it.