I think blending in is the best way, for design purposes if nothing else. The piece of the ad that people click on is the text link which should be the same colour as the rest of your links.
I've heard it said that top right of the page is the most effective position for ads, so that's where I tend to put mine. I usually get between $4-$5 a week from AdSense. I don't have much traffic so that's not a bad amount.
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and it's number 1 if you google 'sligo brothels' 