Sightseeing Sundays: Our Next Big Trip

I thought I would take today to talk about a place that we really want to go next: Ireland. We have made a promise to each other to try and go on a big trip every few years (maybe one day, every year!) and next year, we are trying to save up a trip to roadtrip through Ireland for a few weeks. Rick Steves has an in-depth guide of how to do your very own roadtrip experiencing all the best stops, b&b's, and of course, the pubs.
In doing research, I found that plane tickets are half the cost, or around $700, from October to May. The trip overall would be pretty affordable in terms of an international trip, and Gary is of Irish descent and it would be so amazing to see his ancestors "homeland" and maybe even meet some Russells while we are there. We even rented the horrible movie Leap Year just to catch more glimpses of Ireland. One of my favorite movies is P.S. I Love You, which of course has quite a few scenes in Ireland.
Have any of you been to Ireland yet and have any "must-sees?" Where is your next big adventure to?