Anyone that do not forbid you to use search marketing in TOS. Also you can not use gambling affiliate programs (adwords do not allow it) - you can be banned from adwords if you persist
I know I never had much luck when trying to promote directly to an affiliate link. It was always too difficult to keywords where someone didn't already have that affiliate program referenced. I think you can get a bit better of a conversion by having your own promotional landing page first.
Don't buy any of that mess. Some of it has good quality tips, but everything in any ebook can be found right here. Also, if it is information specific enough (such as keywords to use), they will become oversaturated too fast to make any money using. Read DP and slowly, you'll learn some tricks.
No offence, but do you really think people are going to tell you which affiliate programs they are making money from? Everyone here is interested in internet marketing and making money, so giving out this information would be financial suicide. I wouldn't put much faith in any affiliate program posted in this thread.
I wouldn't advise paying any money for keyword lists - there are a lot of top-paying keyword lists available for free, and your competition for these keywords is going to be immense. I'd advise doing some old-fashioned keyword research and finding the "gems" yourself. Sam
true, they will probably post their own affiliate programs, if one actually knows one which works very good with adwords, he would simply buy more ads to get even more
I guess informational products like ebooks work best with adwords. It can be better if you have your own landing page so that you don't need to overbid other affiliates promoting the same products.