Just thought of a couple more things...by staying at the Westin, the rate inlcuded a full Irish breakfast. We would eat a huge b-fast and eat at a local pub for dinner (about 20 euros for 2).
There are lots of beautiful parks to stroll through (St. Stephens Green was our favorite!)... we also walked down a main road (behind Trinity College) that had row houses with different colored doors (we traveled with our good friends who have a 9 year old boy and he was totally fascinated by the brightly colored doors... took lots of door pics, haha!)
We stayed two pre-nights; and essentially, we walked Dublin for those two days. We would stop at a pub to listen to music in the afternoon (children are allowed during the day), explore a park, and we window shopped at Grafton street (and saw the statue of Molly Malone!), crossed the Liffy by walking over on of Dublin's oldest bridges (the Ha'penny bridge) - lots to see that won't cost you a dime...