I'm not born Irish, but do agree that this visit by the Queen was of huge significance to the overall relationship between the two Islands. It is crucial for Ireland to have it's largest neighbour and trading partner on side as they showed with offering us one of the lowest interest rate bailout loans when we needed it last year (just hope they don't really expect us to pay it back).
Also from a tourism point of view, the tourist board could not have hoped for a better result, early stories of the troublemakers quickly overshadowed by positive sentiment and public events like the scenes in Cork (well done to the Corkonians).
For Barack it was absolutely about electioneering, with some estimates saying up to 36 million Americans claim Irish ancestry, that is a lot of potential votes. But he also genuinely seemed to enjoy that pint. He might be back for leisure sometime when he's an ex-Pres, he likes golf, and pints, no better place to be in my opinion.
On a funny side of our international PR, some clip from one of the US network late night shows, guess the leopard can't shake all its spots...