I've written reviews of quite a few cosmology books on
my website
I think a good bridge between popular works and textbooks would be
Cosmology : The Science of the Universe by Edward Harrison
I've written a review of Julian Barbour's
The End of Time at
http://www.chronon.org/reviews/End_of_Time.html
See also
http://www.chronon.org/books/cosmic_horizons.html
http://www.chronon.org/books/stretchy_space.html