What is the greatest Post Rock band?

Hmm that is a great question. Personally, I am a big fan of Pelican. Now I know that they are technically post-metal, but I found The Fire In Our Throats Will Beckon the Thaw, and City of Echoes to be rather fantastic. Other than that, Explosions in the Sky would probably be my top, I've heard good things about The American Dollar, God is an Astronaut, and Mogwai, but I still have to find one of thier albums...