It is likely best you find a program that makes more of a reseller or broker over affiliate. When you have full control of the pricing above the wholesale you have the potential to make decent money. Look to become a reseller vs. affiliate.
Which programmes are best is all relevant; it all depends on what you have the traffic for or have the potential to have the traffic for. Yes there are some duds, but to find those that work well, you'll just have to use good old trial and error.
If there are any really good ones out there I don't expect anyone is going to tell you which ones they are, they don't want other decent SEO people competing with them if they can help it.
You just have to jump right in and try them and see which work best for you. If something isn't working after a reasonable trial, dump it for something that is, concentrate you efforts into those that do work and work more on testing others, until you can establish a base of programmes that work for you. Once that's done keep testing all the new programmes and other networks and keep going that way.
Which affiliate programmes are best? The ones you find that work for you.