I just wanted to increase my conversion so I am testing new adsense style. Check it out - http://rudefox.com/using-twitter-for-seo/
I think your ad placement is good. I like the square and I think it will do very well. Link title also matches the site. Good Job.
Yes, previously I saw a two 468x60 ads.... now the square looks much better.... and also you have center aligned that vertical banner... good
it is actually against the TOS as this placement will get a lot of clicks for unsuspecting surfers. If you have Ads by Google on top, then it is fine.
Also include link unit somewhere in the page either on top or in the right navigation above "categories" BTW, HSman google suggest us where to include google ads for better clicks in monthly adsense optimization tips. Also the graph issued by google explained some hot areas where we should include ads if you clearly see it, you will find placing ads above the content is not against the TOS.