Oh, you misunderstand me. I know economics, I certainly don't think that FDI does not benefit Ireland. What I meant was some of it is of a nature which might boost GDP somewhat artificially. Isn't Facebook's European headquarters located in Ireland for example? How much of the money brought in by that office (contributing to Ireland's GDP) actually contributes to Ireland? I'd guess a large chunk of it does not. This does not mean that it doesn't benefit Ireland, merely that the benefit does not reflect the size of the GDP contribution.
Indeed, Facebook's European HQ is in Dublin. They employ around 400 people (a third of whom reportedly earned six-figure windfalls from the recent flotation). The subsidiary reported a pre-tax profit of €1.9m in 2010 (I'm not sure though exactly how much was actually paid in tax.).
The presence of Facebook in Dublin helps Ireland's status as a technology and ICT hub - as does the presence of the European bases of Google, Microsoft, IBM, twitter, Yahoo, Paypal and others.
Whether these matters are significant is in the eye of the beholder of course.
This seems backed up by the GNI figures. As you see, Ireland is below most of Western Europe on that measure, indicating that a lot of the money earned in Ireland does not go to Irish people.
True. But then if we didn't have a low corporate tax rate to help attract the various tech companies and the various other MNCs operating in Ireland - the country might surely be substantially worse off in terms of the employment (possibly also the quality of employment) and tax receipts - and quite probably in its GDP and GNI and other such indicators.
And when it comes to inequality, at least what I would mean, is that given a certain GDP level what we think of as standard of living will be lower if inequality is higher. When people are surprised at Ireland having such high GDP this may be based on their impression of meeting Irish people (or just plain ignorance, of course! 
). If there are a few really rich people driving up the average GDP, there can be a mismatch between how rich a country seems to us and what it's GDP per capita is. Brunei or Equatorial Guinea are good examples of this taken to the extreme.
In fact, even the US works. I'd wager that a median income earner in Sweden would seem to enjoy a higher standard of living than all those Americans living in trailers in Mississippi. US GDP per capita is partly higher simply because the really rich in the US drives up the average a lot.
Yeah, as I said earlier, GDP per capita is not a particularly great approximation of "average living standards" (whatever that really means). Too make an assessment of that, I'd have thought that data on average wages/median household incomes; on quality of education, healthcare, etc.; and other matters would be more important.
