SiteAdvisor blog: The Web's Download Disasters, Inaugural Edition
This site is great. It has the list of internet's worst spywares. They have automated testing and have tested around a million spywares. The top five software sharing the honor are above. I came to know that those silly IM emoticons were spyware only after reading it. I see it often in most sites as ads. (i can remember greetings site showing them often).