Google Adsense - How many ad units can be put on a page

Every now and then I get question from somebody, How may google ad units I can place on my page?. All this information is actually available on google's site. I will just put that data in a nice table form so it is easy for you to refer to it. I have extracted this data from google's site. I will suggest that for more accurate and upto date information you do visit the link that I have supplied at the bottom of the post.