Is this placement against the TOS??? I'm having troubles to add 2-3pixels of empty space.. Here is an attachment to see what am I saying...
It looks like it blends in well with the rest of the site. I think it is good placement. Then again I'm new to this as well. I did read Joe Comm's Adsense book, and it said blending was good to make the add look like a part of your site.