I would strongly suggest learning more about the Irish financial crisis:

http://en.wikipedia.org/wiki/2008%E2%80%932011_Irish_financi...

http://www.amazon.com/Ship-Fools-Stupidity-Corruption-Celtic...

There were staggering levels of corruption and mismanagement both in the Irish government and within the Irish financial industry.

I don't think you can look at the corporate tax rate independently from all of the other utterly crazy things that were going on there.