Rot & Ruin and its sequel by Jonathan Mayberry...excellent realist rendition of the zombie apocalypse.

Ugh, I DESPISED Brian Keene's demon-possessed human-intelligence-level, retain the full knowledge of the reanimated body "Zombies"...I don't even know if this really qualifies as a Zombie trilogy. Just my opinion.

WWZ is good...could dredge up some others. Will give it some thought.