While working on one of my WordPress sites I stumbled upon the need to customize (reorder) the column order while I was adding new columns on some admin pages. Specifically in my case, the "Manage Posts" and "Manage Pages" pages. I saw people on the coding sites asking how to do it, with no one responding to them, and I was unable to really come up with a simple example by doing a little Google-Fu, so I figured it out on my own and thought I'd share.
All you really need to do is shuffle around the $defaults variable (which is an array). Here's the code: