I would also add to your list:

* http://www.informatik.uni-trier.de/~ley/db/conf/dbpl/

* http://arxiv.org/corr/home

* http://citeseerx.ist.psu.edu/index

* http://rjlipton.wordpress.com/

* http://www.scottaaronson.com/blog/

* http://scientopia.org/blogs/goodmath/

and the like