First, you have some errors on your site, my explorer freezed when I visited your site. second, I would recommand you to move one ad to the bottom of the page. third how about a FF ref. ad in the sidebar?
In my experience if the first thing a visitor is encountered with is a huge ad unit it is off-putting. I therefore recommend removing the top leaderboard. I'm also concerned that 75% of your content 'above the fold' is ad - too much. Better to space your ads out down the page - ideally placing them between posts.
The placement is pretty ordinary, I would suggest making your table's background (the 2nd one) a darker shade, and match that ad unit with the same color. There's too much white on the page.
Your ads stand out and are away from the content. Looks more like all the Ads unit make one half of your page. Try to get them as close to content as possible. Put ad units between two posts and that should be better for your site. Use horizontal link ad unit too.
I think you should have content to wrap round with the Adsense ad to blend in as it will look as part of the content. Your ads placement is within the Red Hot Zone so it should be able to draw more clicks. Regards Edward Han