I do this, why remove an income source?
Selling private ads next to Adsense ads still seems the best combination IMO
Also, I don't like the idea of going out looking for Advertisers, they come to you if your site ranks for their keywords, you just need to provide a means to be contacted. And to automate the process you can sign up with a service such as Text Link Ads (they advertise your link spot but take a chunk of the revenue). But you don't have to do any work apart from a cut and paste of some code.
Looking forward to a non-theoretical post on your blog showing revenue results
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