I am using 468x60 text banner ad on my blog. It appears below the header and above the content start - prime location . The advantage of this ad is there is no url listed in this ad. So the person has to click on title to go the site.
Yep, large rectangle is the clear winner. One thing I'm wondering though is where you guys put it on top of the post? For my part I don't wrap text around it, I only put it on top and text below. Do you guys use left align with wrapped text on the right?
I use 468 x 60 text banner on the top of my blog and a large rectangle on the right side. I find this arrangement is more useful.