Quality content. Deliver a quality article to a quality article directory like ezine or hubpages and you will get juice. One good quality article is worth more than 1000 of these crappy articles from no name web2.0s. Taking one article and spinning it 50 times to a bunch of garbage no matter how you link it is useless.
The effect is pretty minimal, especially when compared to a link from a real site placed by a real person. If no human will actually link to your site, then you might have to depend on link wheels.