Tom has put together a WordPress Theme Viewer with 39 themes. Many of these themes have been announced here before and before anyone asks, Tom has no plans to update the viewer with new themes. You can download the themes in his viewer from this list.
Another reason for this post is to draw attention to some of Tom’s work and the reason I want to garner that attention is because I believe that his work can be really helpful to novice bloggers. He is a technical writer and podcaster and has a lot of good things to say on and about WordPress. He has written on themes (on which the theme viewer was based), plugins and various other WordPress and blogging tips and tools.