Anyone know which affiliate marketing networks can I make the most money from?

There are a lot of web affiliate marketing networks (Commission Junction, Hydra Networks, etc). Can someone tell me which is the best?

I am researching online affiliate marketing. Say I am looking to sell something online. Let’s also say I want to leverage affiliate marketing networks to advertise my product. As the merchant, is it common to have the ability to choose which type of advertising channel you are marketed to or is it more like a shotgun blast across the internet?

Or is it the other way around… do the affiliates choose what is eventually advertised by their site?

I have been using Clickbank for affiliate marketing products for the past 4 months and I just made the payout last week since you have to have 5 different transactions to get your first payout. I only do affiliate marketing part-time on 3 blogs and 1 niche website, but I would love to eventually do it as a full-time job and make more than a month to do so. For people who have experience with different affiliate marketing networks, which one do you see the most sales and income from?

I use cj, copeac, and a few others but I am looking to expand into more. What are some other good affiliate marketing networks?