I place a AdSense link unit just below Text-Link-Ads and Chitika Affiliate Banner and got huge success, but I wonder whether its against AdSense Terms of Service (TOS)? Can anybody suggest ??
I am not so sure about this. it could be deemed that you are drawing attention to the link unit by placing it so close to that particular ad.
Google might consider it just as an image and ask you to separate the two a little bit. Keep us updated please if it's still working.