OK, it all depends on how much time you have. I'd advise avoiding Temple Bar, but if you want to go for the experience of diddly eye music and crowds just walk around for an hour. Mad expensive there.
The natives go to Camden Street, South William Street, Dawson Street, and Sth Anne Street areas. So much there, look on the map.
Where you are staying is right beside Trinity College Campus. Go out to Pearse Street for cheaper eats and drinks - it's a studenty place, so while still expensive by other standards it is cheap for the natives! If you have time walk down to Grand Canal Square, there is a Wetherspoons there overlooking the water, and a great buzz about the place, it is off Pearse Street, top end.
On the other side of the river is the Financial District, but there is a great spot there called The Harbourmaster Bar, and Urban Brewing. It is near to o2 Arena so avoid on concert nights!
Take the DART rapid rail from Tara Street station to DunLaoghaire and walk along the pier, a famous and much loved pastime for native Dubs. Also, you can take bus no C1, or C2 from Pearse Street to charming Sandymount. It only takes ten minutes and you are by the sea, there is a great walk all along. The village has numerous pubs, eateries, and quirky shops. Handy for getting away from the city in a jiffy!
Ask away if you want/need more info.