By now you've probably had your Intel NIC/motherboard/ubuntu problem solved.
I'm facing something similar with a DP67GB motherboard (on-board Intel 82579v network interface) with Ubuntu 11.1
I get ethernet connectivity, but at a lower speed (10)....
I'm sure its a matter of drivers, and/or settings on ubuntu.
Was wondering if you got a response to your request, and if you could share those contacts, or responses with me, so I can continue searching for an answer.
I really appreciate your help.
I figured out my problem. A little outdated switch/hub I had connecting my desktop to my home network did not quite understand the Intel NIC autonegotiate function. After leaving the problem unsolved for a while, I started playing with ethtool and changing speed and duplex.... ethtool could not report certain changed values, and I was about to get a new switch (the old one was only 100 speed capable anyway). So I thought I'd connect the desktop directly to my 1G speed router. And that solved the problem. My Intel NIC is happily talking at 1G speed now, full duplex. So getting a new switch is not as pressing an issue anymore, and I can transfer files at a decent speed. So, don't be so quick to judge your computer hardware, before checking your network hardware first.