After installing the MacBook Pro Software Update 1.4 and EFI Update 2.1 my ping times are much lower and consistant while the network usage is at idle. Maybe Apple slipped in a fix for it without mentioning it.
PING 192.168.7.1 (192.168.7.1): 56 data bytes
64 bytes from 192.168.7.1: icmp_seq=0 ttl=64 time=1.448 ms
64 bytes from 192.168.7.1: icmp_seq=1 ttl=64 time=3.582 ms
64 bytes from 192.168.7.1: icmp_seq=2 ttl=64 time=0.960 ms
64 bytes from 192.168.7.1: icmp_seq=3 ttl=64 time=1.768 ms
64 bytes from 192.168.7.1: icmp_seq=4 ttl=64 time=1.182 ms
64 bytes from 192.168.7.1: icmp_seq=5 ttl=64 time=4.385 ms
64 bytes from 192.168.7.1: icmp_seq=6 ttl=64 time=1.004 ms
64 bytes from 192.168.7.1: icmp_seq=7 ttl=64 time=3.438 ms
64 bytes from 192.168.7.1: icmp_seq=8 ttl=64 time=2.560 ms
64 bytes from 192.168.7.1: icmp_seq=9 ttl=64 time=3.479 ms
64 bytes from 192.168.7.1: icmp_seq=10 ttl=64 time=1.445 ms
64 bytes from 192.168.7.1: icmp_seq=11 ttl=64 time=3.422 ms
64 bytes from 192.168.7.1: icmp_seq=12 ttl=64 time=1.145 ms
64 bytes from 192.168.7.1: icmp_seq=13 ttl=64 time=1.220 ms
64 bytes from 192.168.7.1: icmp_seq=14 ttl=64 time=1.240 ms
64 bytes from 192.168.7.1: icmp_seq=15 ttl=64 time=1.763 ms
^C
--- 192.168.7.1 ping statistics ---
16 packets transmitted, 16 packets received, 0.0% packet loss
round-trip min/avg/max/stddev = 0.960/2.128/4.385/1.115 ms
This is while at work, my previous posts in this thread include tests from both work and home, both of which were bad before.