@nomis5: Okay, thanks for your input buddy. But does it really matter? let me know so that i too make the change.
Also just wanted to add, i am using a plugin for adsense ad to display and i have left the setting for 300x250 ads as "random" instead of placing them either to the right or left. So they keep roaming everytime you refresh the page. you will find them in new place always.