I've rented with AutoEurope in Italy. Very good rate, no drop-off fee if returned within the same country as where rented. There is a 3-day minimum rental.

If you're renting more then 17 days they also have a "buy back" program where you are provided with a brand new Peugeot for the duration, at a lower daily rate than a normal rental (includes insurance). As I recal there was a pretty substantial delivery fee outside of France, but it's worth running the numbers.

On the topic of Ireland rentals, I see that AutoEurope has a special $14.99 rate for Ireland rentals beginning between April 19th and April 30th.

http://www.autoeurope.com/showspecial.cfm?specid=114