According to Google, Adsense Ads embedded directly in content have a highest Click through Rate(CTR).
For Joomla site, there are a lot of choice to show Google Adsense, but the best way is to embed Adsense directly in your content. Here I recommend a smart Joomla plugin:MultiAds. It allows you embed Adsense code into article content automatically, which makes Joomla easy and effective to show Google Adsense.
Joomlatags.org has used MultiAds to show Adsense.