Here is one advice from AdSense, right on the adsense admin dashboard : " Opt ad units into both text and display ads Enable ad units to display both text and display ads. Ad unit "BTA 200x90 Top" is currently able to receive only text ads. To maximize your revenue, opt in to displaying text and display ads." So, here's why YOU are way more intelligent than AdSense : The ad unit "BTA 200x90 Top" is a thematic links unit (Ad type: Links ads only), not an ad unit .. So it can only display text links, not even text ads, even less graphic ads.. YOU would never be so stupid as to advice someone to opt in to display text and display ads on a thematic links unit.. And you didn't even create the damn thing! So now, the monkeys working there are not limited to banning accounts, they have invaded the content writer and programming departments too..
I have always liked to have up both ad units that display text and multimedia, which have always proven to be the best.