Ethernet, not WiFi. None of the models have wireless. A wireless module costs nearly as much as the entire board in parts.
You can easily add wifi using this $10 dongle: http://www.amazon.com/gp/product/B005CLMJLU (according to the rpi forums, it works out of the box with current kernels)
I can't really agree with this line of thought:
802.11a - 1999 (5GHz)
802.11b - 1999 (2.4GHz)
802.11g - 2003 (2.4GHz)
802.11n - 2009 (2.4GHz + 5GHz)
802.11ac - 2012 (5GHz)
The only new standard on the immediate horizon is 802.11ac, and that's targeted strictly at the 5GHz band. Additionally, all the 2.4GHz stuff is backwards compatible all the way back to the old 802.11b standard.
Things certainly change, but it's more in the range of once every 4-5 years than it is all the time. There are good reasons not to include wifi on-board on the pi, but I don't see that as being one of them.
It also normally requires you to either get emmisions tests for the complete system or you can use a separate WIFI module - which is why most laptops have wifi on mini-pci cards.
Of course if you want to make a no-name $5 usb wifi dongle and just print CE on it that's a lot cheaper.