http://msinfluentials.com/blogs/jesper/Default.aspx
Jesper Johansson
http://www.msmvps.com/blogs/alunj
Alun Jones
No disrespect intended as I find out about SP releases that way, but MJ Foley, Ed Bott and Bink I wouldn't exactly call security. While they do have security related topics, they are more for keeping a finger on the pulse of Microsoft in general.