In the city the Crown & Sceptre is fresh, funky and they look after you... Electric Light Hotel cocktail room is also very cool room if you want something a bit different. The Bull & Bear on King William is also worth a look.
As for outside the city I went to a party recently downstairs at the Oriental on Magill rd (Dyanasty). They've got a sweet setup down their, although I heard they soon may not be hiring out the space anymore.