What is the best Pay-Per-Click Publisher Program?

I’m using AdSence since I know myself .. but I never took the challenge in putting up some other ppc ad network. I red articles that combining ad networks like – if someone finds your site from google you should show him overture ads and via verse … but I never actually did it because (I was too lazy he he he … ).
So now I’m interested in upgrading some of my sites and I was wondering what to put in addition to AdSence ?? Any suggestions/recommendations ?
Thanks,
Venetsian.

Original post by venetsian