Weird AdSense Ads

I author a number of blogs. Currently they are all hosted on Blogger. And for the most part, I have Google AdSense ads displayed on these blogs. A nice ad format is the 160 x 600 shown directly to the left. This format is a tall one that lends itself to the right or left of a blog nicely.
However I have been noticing that sometimes one advertiser takes up the whole 160 x 600 ad like the one shown on the far left. I really don't like that. It does not look as good, since there is a lot of empty space. It also provides less ad options for the user to click.
So far I have been adding the URLs in the weird ads to my AdSense competitive ad filter. Google will then prevent these ads from displaying on my blogs. But this is still a weird effect. I also think this is wasting my slots in the competitive ad filter list.
This is really more of an AdSense issue than a Blogger one. I just wish there was another way to eliminate this weird ad distribution of one in a 160 x 600 ad format.