If you want to generate tag clouds for your blog manually, tagcloud-generator.com is the tool you should use. This tool allows you to generate tag-clouds based on the links on your blog (see screenshot below) or the most frequently used words on the blog.
You can remove or add tag-clouds as well as change their look and feel. The final code will be an HTML code styled in CSS.
Have never used a single tag ever since I began blogging… only categories
Tags take quite some space of your template, i don’t have much space.
This one is good too: http://www.tagcloudgenerator.com. You can change cloud’s appereance by selecting color, font, etc.