I'm currently mostly on adsense. But planning to move to affilate. To live on adsense, you need a LOT of traffic. We are talking about a million page view per day. That is hard unless you have very good content and keep it updated daily. Affiliate network is a better pay but it's hard to find a good niche that can make you money.
I would not want to be totally dependent on Adsense. Google can change your revenue in so many ways that you have absolutely no control over. Mine is about 25% Adsense, 40% affiliate programs, and 35% sales of my own online service. Al
Google makes a nice additional income, but I don't think I can rely just on the ads to make a living...My business comes first.
I spread our income between affiliate stuff, adsense and ecommerce. I agree with everyone here who says it is a bad idea to put all your eggs in one basket.