I opened a savings account with National Irish Bank recently, they have a rate that's guaranteed 0.5% above the European ECB rate until end of April 2008 (I think). At the moment this makes the rate 4.25% which is good. You can have immediate access to your money, and contrary to RaboDirect this is not an online bank so you have the possibility to go to your NIB branch if needed.
I have a regular account with them as well and I am very happy with their services. They have no charges.
To compare interest rates go to the Financial Regulator on Dame Street, they have just published a very good guide on savings account.