MickThe merchants is good craic (only problem is it's really a Kerry Pub ah no really It's a good GAA pub) there is usually a mixture of set dancing and ballads on a Sunday night, the atmosphere is really good. There is someone playing guitar and singing from early so there's no excuse not to be sinking a few at an ungodly hour. there was a thread on Dublin Pubs a month or two ago.
Enjoy
Gearoid