Most of the email and click sponsors that are still alive suck or your losing money one or the other .
I think your best bet is asking what sponsors are doing the best
Nastydollars is converting very well lately a few downtimes though.
Pornkings and wegcash is tossing way to many banners at your visitors.
Playboycash is also tossing a few too many banners at the visitors before an attempt at a sale is made.
Nastydollars pays everything to you, theres only 2 things i would like to see better.
1. They offer an email signup on the main pages and your not paid for those and your ref code doesnt follow the email
2. Webmasters ref codes ( for other webmasters to sign up ) are not passed along with your click ( alot of sponsors are doing this now , and its nice to see. )
It all depends on your traffic as with any sponsor/program in the end.