Twilight of Arnor, check it out:
http://www.gamespot.com/pc/strategy/galacticcivilizationsiitwilightofthearnor/news.html?sid=6177058
I think biggest addition:
Unique tech trees for each race.
http://www.gamespot.com/pc/strategy/galacticcivilizationsiitwilightofthearnor/news.html?sid=6177058
I think biggest addition:
Unique tech trees for each race.