Configure Login Audit - Skip one user-
You cannot do it there.  But you can set up a server audit and exclude specific login.  I have not tested the code in 2008 R2.  Change you login value with LoginName. You can also use server_principal_id instead of server_principal_name.

USE [master]

GO

CREATE SERVER AUDIT [FailedLogin]
TO FILE 
(   FILEPATH = N'C:\'
    ,MAXSIZE = 64 MB
    ,MAX_FILES = 50
    ,RESERVE_DISK_SPACE = OFF
)
WITH
(   QUEUE_DELAY = 1000
    ,ON_FAILURE = CONTINUE
)
WHERE server_principal_name &lt;&gt; 'LoginName'

GO

USE [master]

GO

CREATE SERVER AUDIT SPECIFICATION [ServerAuditSpecificationFailedLogin]
FOR SERVER AUDIT [FailedLogin]
ADD (FAILED_LOGIN_GROUP)

GO