Note: This continues to be considered to become a duplicate of some other:

Do not answer that one. After I learn how to slowly move the solutions to that question, I'll remove that one.

Original question:

I'm evaluating CSS grids for multi-column internet sites, and taking advantage of Wordpress for straightforward content management on other sites. Let me try the grids around the Wordpress sites.

Which frameworks integrate best with Wordpress?

Presuming you are building your personal Wordpress template, there is nothing specific to Wordpress that require influence your choice.

Grids and Blueprint are generally great choices for multicolumn designs.

Some people have produced ready-made Wordpress styles using Blueprint:

These might function as good beginning points for any design.