I will list the first book in the series but try and tell you how many books there are so far:
Gone by Grant Baker (total of 3 so far, I've read 2, so I don't yet know if the 3rd is the last) - set in and around a town on the California coast, in the blink of an eye all the adults are gone, and the teens and kids come to learn they are trapped inside a dome that encompasses several square miles. Some of the kids develop odd powers, and there are two factions (of course) fighting each other.
Life as We Knew It by Pfeffer (series is complete at 3 books) - an asteroid hits the moon and pushes its orbit closer to the earth causing climate changes, tsunamis, etc. First book is the best.
Maze Runner by Dashner (2 books so far, I have but have not yet read the 2nd book) - a teenage boy wakes up in a type of elevator that is taking him upwards to a garden acreage area where there are only teenagers. The land is surrounded by a maze that is deadly if you venture into it after dark. What is in the maze, and is there a way out?
The Uglies by Westerfeld (6 or 7 books in this series, I forget) - at the age of 16, everyone gets plastic surgery to become pretty, but a rogue group of people don't think that's right. They try to rebel against society and the government.
Shadow Children by Haddix (7 books, first one is Among the Hidden; series complete) - this one is shelved in Independent Reader, but is still very captivating. The government has passed a law stating that families may only have 2 children, but people break the law and subsequently must keep their 3rd child in hiding lest the authorities find out. The Shadow Children find each other and plan to overthrow the government.
The Limit (standalone) by Kristen Landon (might also be shelved in Independent Reader but really is more of a YA title) - the government has given every family a budget. If the family overspends, then they must send one or more of their children to work off the debt. The main character is super-smart and gets sent to a place where he and other kids are doing strange computer work and experiments.
Not post-apocalyptic but still fantastic:
A Great and Terrible Beauty by Libba Bray (3 books total) - set in a British boarding school in the 1800s, teenage Gemma learns she has the ability to cross over into another realm, and there are dangerous people who will kill to get access to that realm
Books I've have bought and am pretty certain I will like:
The Forest of Hands and Teeth by Carrie Ryan - a post-apocalyptic romance
Dies the Fire by S.M. Stirling - in adult sci/fi; first in a series; recommended by one of my GMs
The Knife of Never Letting Go by Patrick Ness (Book One of Chaos Walking series) - Todd lives in a town where everyone can hear everyone else's thoughts; he stumbles across an area of complete silence and discovers that something terrible has been hidden; they must run, but their pursuers can hear their thoughts