Some plugins, like Ultimate Tag Warrior or Amazon Media Manager, bring their own icons with them. Often, they don't fit the template/design of your blog. So, you could either do nothing, or you overwrite the default ones with your own any time you upgrade the plugin.
And beacuse that's annoying, I had an idea for this: If the plugin just looks in a pre-defined folder in the template (like TEMPLATE_PATH/plugins/PLUGIN_NAME), if there are nicer images to display, it uses them. If it doesn't, it uses the default ones.
What do you think about this? Would it be good/bad/ugly?
More at my blog: http://www.creativelycrazy.de/wordpress-plugins-images-in-themes/
Sid