Tag Clouds have been bugging me for ages, and I have just installed, WP Category Tag Cloud, which is pretty awesome. I have used the short codes to set up a tag cloud on its own page, and also installed a moving three-D cloud on the About this Wiki page. The featured picture is a picture generated by tagcloud.The parameters are documented on the FAQ page, I restricted to the tags taxonomy, varied the number, and set format to default for the list and to array for the mobile 3d tag cloud. No doubt this can be used to replace the category list on the widgets page to do 1st level categories only.
This needs to go on the blog.