Post hardcore is a bit of a broad genre.

Some bands that fall somewhat under that category would be:
Underoath
Thrice
Saosin
Poison the Well
Silverstein
In Fear and Faith
From First to Last
At the Drive In
The Fall of Troy
Attack Attack
Chiodos

I don't actually listen to like any of these bands so I can only tell you what my friends who do listen to this stuff say.