Jonathan - 8:06 pm on Oct 5, 2011 (gmt 0)
I've tried Media.net. The revenue was close to Adsense, and might be higher for some. You can also run it alongside Adsense.
I applied to Federated Media; never heard back. I think I'm going to follow up today, I hear good things about them.
At very least, it's good to check out these services in case you get dropped from Adsense.