Genna's is definetly one of the nicer places to drink on the capital square! The drinks are reasonably priced and if you come here during the day, the menu is very tasty! (although they cater from next door, so it's not really Genna's food)
I agree with the other reviewers about getting here early and claiming a table otherwise you'll be stuck standing all night. During summer you can sit outside in the patio area, which is nice for watching people come and go.