Ireland is a land of drinkers, but not of beer bars. 
All of the pubs serve Guinness, Smithwicks, Heineken, Carlsburg, and Budweiser. 
A bigger bar will have more towers repeating these same beers. 
Really big bars may also have a single tap of Kilkenny, or Beamish, or Coors.
The liquor stores in Ireland are similar to those in Maryland, in that they sell wine, liquor, and beer. 
A typical beer cooler will have multipacks of the various sizes of bottles and cans of Guinness, Smithwicks, Heineken, Carlsburg, Budweiser, Coors, Miller Lite, and Corona, along with a selection of canned lagers from Eastern Europe.