In Apple's press release for the iMac, they make a small note that the Airport Extreme has been updated to include gigabit ethernet.
Apple's 802.11n Airport Extreme base station had only included 10/100 Base-T ethernet, which had been a sore-spot in reviews considering all Macs now ship with Gigabit ethernet, and the theoretical wireless performance would outstrip the wired performance.
As of this writing, Apple has yet to update the product page for the Airport Extreme to reflect the change.
Related Forum: Mac OS X Server, Xserve, and Networking
