For tier 1 content, I create my own. I use Ubertoolz to create readable, highly unique articles:
http://www.blackhatworld.com/blackh...ing-unique-content-creation-toolset-live.html
The other benefit of Ubertoolz, is that you can create unique titles as well. Put in your keywords, and it will spit out the titles. Rankwyz has a title builder that works, but I prefer the one in Ubertoolz.
You can also create your own articles using Matt Woodwards formula:
http://www.blackhatworld.com/blackh...rly-advanced-article-spinning-techniques.html
For tier 2/3 content, you can use the Rankwyz syndicated content or create your own with Kontent Machine / Article Builder.
I organize my blogs by niche or website. So I am creating themed/niche blog networks. I post 1 to 5 times on them without any links, and let them age from 2 to 6 weeks. Then I start posting articles with links. You can drip out your posts, with the scheduler. I like to create lots of articles, and have them drip out over 100+ days. That way you have a steady amount of links hitting your sites on auto-pilot at a even rate.