I agree with Ryan Caldwell (performancing.com) :
So the first step in my adventure was to prettify [my pages] a bit. To do this, I downloaded the Category Icons plugin for WordPress. Category Icons allows you to associate a unique image with each of your WordPress categories. By placing a little snippet of code on your category.php theme file, you can then have a big, bold image come up that will make your category pages look better than 90% of the category pages out there.
Or with JTPratt when he wrote :
It’s a beautiful plugin [...] well documented and supported. Everything is configurable from the options menu, you can use it on your index (home) page, post pages, or even your sidebar! You can do icons only, or text and icons, and it comes with a widget for the sidebar.
The cool thing about the plugin is that it gives you ways to do one or multiple category icons, but also a method for putting icons with your categories in the side bar as well ! I’m always very grateful when a good plugin come along !