Guinness (I think tours end by 5:00 but their store is enormous. Check the times before you go.)
Templebar - Entertainment, best bars area and probably where you can get that pub tour.
General Post Office on McConnell Street. Historic spot, and interesting art inside tells story but you'll get more out of it if you read 1916 which I'm mailing.
Trinity College - Book of Kells. Definately a must see! The display is way more interesting now than it was back in 1981. Big improvement. They really explain the process.
Kilmanhim prison (past Guiness Brewery), but only if you get time to read books about it's significance. Otherwise just an old prison.
Dublin Castle (for the Georgian architecture. Not really a castle, but intersting.
There are some interesting old churches like St. Patrick's and Christ Church. Christ church used to give you an opportunity to walk in an area with a zillion old crypts where people are buried. Hair on my neck stood up! I really felt it was haunted. But now you can't see that. They cleaned it up and plastered over the walls where people are buried --it just looks like a low ceilinged white painted area. No more creepiness). St. Patrick's is interesting for the architecture.
Newgrange: Megalithic tomb north of Dublin. Thousands of years old structure. Never saw anything like this anyplace else. This is the place where the Dec 21 sunrise shines directly inside to a certain spot used for rituals in ancient times. Take bus tour to get there.
Jameson distillery is in or near Dublin
http://www.dublintourist.com/details/the…Waterford: Waterford Crystal factory tour.