I've just got back from a trp to Dublin, we went to the book of Kells which was good, but the old library also included in the tour was fab.
I went to the Guiness tour and Kilmarnain Gaol. The Gaol tour was very good.
Other than that I just ambled about on the Dublin bikes enjoying myself!
Can't recomend any B&B's but we got a good deal at theCardiff Lane Maldron Hotel on Expedia, very nice it was too.
We had booked a tour with Dublin City Bikes but it was cancelled due to bad weather, shame too as it has very good ratings on trip advisor.