Best CPM Network ?

Hello,
Can anyone recommend me a good CPM network with high CPM rate ?
I currently use CPX Interactive.
I had applied for Tribalfusion, Casalemedia, Fastclick, Valueclick and they have not accepted my sites.
So, can anyone recommend me one that accepts most sites ? i mean, my site is not very big and not small too.

Thanks,

Original post by .Darkman