Top PPC search engines?

After google, yahoo and msn what are the top search engines that offer their own unique PPC marketing programs.
I allready have Miva, GoClick, 7search, search123, searchfeed and enhance but I am looking at adding to my list.
If anyone knows of other good ppc search engines or ppc networks, I would love to hear about them. THanks

Original post by shieldsty