I used to think organic search engine is the best, but when your ranking changed your traffic is gonna dramatically change and there is nothing you can do. So I'll say traffic from newsletter is the best.
Depends what you mean by best... In my case I would say my best traffic is traffic that converts. So I would agree with you that the best traffic comes from targeted email newsletters.
I tend to get very good results by making use of EZine articles as well, tend to generate quite a lot of traffic through them.
Yahoo answer? I never had much luck with it. Most of my traffic come through my personal blog, facebook and twitter.
SEs are still the best, but you need to have plenty of sites, so when goes down, another one goes up and you still get enough traffic and make decent amount of cash...
Obviously i'm going with Banner Ads A good looking, well places banner ad can bring in a lot of traffic.
My favorite traffic source is other websites. When visitors come to my site from other websites they usually have at least a basic sense of how to use the Internet and a web browser. It's tough when someone comes from somewhere other than another website, for often times they do not know how to use a website and because of this they are unable to contact me and ask how to use the website. Therefore I never know they even exist.