I would like to recommend the James Joyce Irish pub & restaurant, Astiggos 12, Thiselo-Monastiraki. Great atmosphere, friendly staff & the owner Tom makes you feel very welcome. Great place to meet friends to eat & drink, Guinness, Kilkenny beer & we think the prices are good.
The menu is superb with irish soda bread, steak & guinness pie, sausage & mash, ploughman's lunch, salads & pasta dishes & much more. They also do a wonderful hearty irish breakfast including my favourite white & black pudding which we are going to try next weekend. The website has the menu but it is still "under construction" http://www.jjoyceirishpubathens.com/
It is very easy to get to:- Go to Monastiraki metro station, head towards the Flea market, at the end of the Flea Market turn right, 1st left & it is on your right
Hope you enjoy it as much as we have