CJ Affiliate – Go to place to find offers from a wide variety of vendors and niches. 400-day cookie lifetime.
Shareasale – Even more offers to choose from than CJ Affiliate (6000 to 3000). Looses out to CJ Affiliate due to CJ Affiliate long cookie time.
Amazon Associates – Everyone is familiar with Amazon. It has one of the biggest affiliate programs on the planet to help sell it’s products (around 12 million offers). Has the negative of a short cookie time (just 1 day).
Ebay Partner Network – Just like Amazon, everyone should be familiar with Ebay as well. It has even more offers than Amazon, but due to the auction model of it’s sales and a short cookie time, I can’t rank it higher.
Clickbank – A decent affiliate program, exclusively selling digital products. Generous commission model (40%). Calculated not as a percentage of Clickbanks earnings but on offer owners revenue. Two payouts per month which is nice.