These are the address ranges to be blocked out-bound, as of early 2012:
Code:
CIDR: 23.0.0.0/12
CIDR: 50.16.0.0/14 (the log collector)
CIDR: 72.21.192.0/19
CIDR: 107.20.0.0/14
CIDR: 184.72.0.0/15
CIDR: 204.246.160.0/19
CIDR: 205.251.192.0/18
CIDR: 207.171.160.0/19