the nature of risk/reward is that the "completely safe" does not have to pay high interest rates to attract deposits. So on that basis your first criterion would be Rabo where you can earn 2.25% on demand. Their rating is the strongest you can get at AAA. If it is good interest you want then buy Irish Government Bonds where the yield would be about 8% for buying e.g. sep-2012 bonds. But then you have a high risk of default and a rating of close to Junk.
If you are even mentioning the words completely safe, means that you should put your money into Rabo. Certainly not one of the poorly rated local banks, Post Office etc.
