I have recently added several new blogs to the blog roll which I encourage you to try out:
Sean Carroll's Blog
Going out, due to inactivity for a prolonged period of time are:
Minoan Language Blog (last post September 30, 2012),
A Very Remote Period Indeed (last post February 27, 2013) (reluctantly since this has a local author), and
The World According To Kevin (last post August 15, 2012).
I am being quite lenient in my culling. Several other blogs on the blog roll are quite inactive, but none of the others appear to be truly abandoned.