Andreas Hecht

Creates a new and simple to use widget that adds a tabbed sidebar box with recent posts, last comments, categories, popular posts, a tag cloud and the archives to the sidebar. No Options. This widget is perfect for light-colored themes.
To use the widget, go to Appearance -> Widgets and add “AH Sidebar Box” widget.

AH Sidebar Box

This widget adds a tabbed sidebar box with recent posts, last comments, categories, popular posts, a tag cloud and the archives to the sidebar.

Waterloo Plugins

Tag Cloud Widget adds a simple tag cloud widget that you can use anywhere on your blog. This plugin looks at all your tags and displays them in a widget. The more times a tag is used, the larger the tag is.
Each tag is a link to the tag page (e.g. http://your-site.com/tag/your-tag). This will help with SEO.
Currently, there aren’t any options to customize the tag cloud. It should work well out of the box. In the future, there may be options to customize the widget.

Good

A tag cloud widget with links to your tag pages

AH Sidebar Box vs Tag Cloud Widget