Echoing some already named:
Bon Iver - For Emma Forever
The National - High Violet
Decemberists - The King is Dead
Beach House - Teen Dream
Grizzly Bear - Vekatimest
Deerhunter - Halcyon Digest
Radiohead - King of Limbs
Vampire Weekend - Contra
Yo La Tengo - Popular Songs
Not all new in 2011 but very high quality and new to me!
Bon Iver - For Emma Forever
The National - High Violet
Decemberists - The King is Dead
Beach House - Teen Dream
Grizzly Bear - Vekatimest
Deerhunter - Halcyon Digest
Radiohead - King of Limbs
Vampire Weekend - Contra
Yo La Tengo - Popular Songs
Not all new in 2011 but very high quality and new to me!