There are so many places to get traffic these days, it is silly. The question is getting convertible traffic and converting it, and that is a never ending process of the Scientific method.
Sources of traffic
SE's though basic and advanced SEO techniques on a wide variety of sites - there is a reason that tubes do well on SE's.
Toplist and hardlink traffic trading
Skim traffic trading
Plug trading
Link buying (You can buy legitimate links that do not violate SE policies)
All types of traffic is available for sale - SE clicks, banner, text, force, popunder, etc.
Submitting galleries and sites
Good traffic management (hub and spoke) to multiply your traffic through your other trades as well as filter it - one click becomes 20.
Hub partnering
Build an affiliate program
Clip share type submits
Build your own landing pages to recycle non-join page traffic
Build your own galleries per site and use them throughout your network
Surfer forums
Social networking - twitter, facebook
Unlike many years ago, there are many, many sources of traffic. There is also more competition for it and more of that traffic is useless as much of the non-cc holding world is now on the net.