I have succes in the past with blog netowrks.
First I have used different small networks, like guest posts with links in my article, that worked great for some period of time.
Later I have tried some other paid networks(on monthly basis), best that I have used is :
Backlinksolution - they don't accept new members, you need to subscribe and they mail you when they got some available places.
Freetrafficsystem - not so great results
UAW - dificult not much luck with them(I think isnare is better)
AMA - some good results
What about you?