You get to carry that NIFTY GREEN passport. 

And, Gives you the right to crab about IRISH politics.    
Seriously:
You can live and own property without becoming an Irish Citizen, but if you AREN'T an EU citizen, you can't be employed without a Green Card, which must be applied for and approved by the Irish government.  There are a NUMBER of restrictions / tests involved in getting that approval.

The US government really doesn't HAVE a possition on dual citizenship, Pro OR Con.


Here is a link to a LENGTHY discussion on the vagarities of dual citizenship:
http://www.fodors.com/forums/threadselect.jsp?fid=2&tid=34560097

Bob

-- Edited by Itallian Chauffeur at 22:58, 2007-04-12