Dude..
Just look around. Adsblacklist which lerchmo suggested is a very good place to start. Other than that, just look around on the top listed ads for any niche in 7search.com. Most of those are likely doing pretty well. If in doubt when you see one, just apply the rules of arbi templates as discussed in this forum earlier.
To sum most decent templates;
- as good ad blending with content as possible. (adjust font/style sizes and colors)
- very few or no images. If used, be sure to separate from ads
- keep it simple and even ugly if need be
- no outbound links (Unless you're going for Adwords traffic, in which case you want to kiss Google's ass by giving them some on-page links, privacy policy, about us, and other shit)