The WordPress Codex lists some plugins for adding moods to posts
Moody: Enter your mood in the Custom Field section of your post entry and the plugin will display in your theme below the time.
Sounds good but the plugin doesn’t work with WordPress 2.0 and up. Plus you have to do your configuration in the php file.
Mood Quote: Let’s you assign a quote for your mood. Interesting plugin though it’s not what I need.
Cricket Moods: This plugin lets you assign moods with images so whenever you put a mood in your entry. What’s good about this plugin is that each user can customize their own mood list and you have the option to automatically show the mood or position it in your template.
MyMooMus: This is a three-for-one plugin, combining the display of moods, music and tv in your posts. However it only shows the text not images.
I’ve made my own plugin that lets you set the location of your mood directory and image extension. In the Write Post screen, select a mood from the drop-down list of moods. There’s also a template tag to display the mood in your template. It’s not available to the general public because I’m still testing and adding features but if you’d like to try it out, drop me a line and I’ll send you the file.