I think you’ve got it backwards. Try
order allow,deny
deny from x.x.x.x
allow from all
That should block all URLs from that IP.
And Limit Login Attempts http://wordpress.org/extend/plugins/limit-login-attempts/ can be set to not email you with each lockout. Set the lockout timeouts to 9999 hours, too, which is the maximum setting.
If things still don’t work, deactivate other plugins that might be intercepting calls to or reads of .htaccess.