The Old Quarter and Nancy Blakes are good bars with plenty of activity, and down to Trinity Rooms if your heading on to a nite club, all in and around the same area so no taxi needed
Nancy Blakes (late bar)
Flannerys (Next store to Nancy's late bar)
Smyths (Across from Nancy's) They also have club Icon (Tends to be young)
Mojo's
Aubars(late bar) disco down stairs.
I think the Italian mentioned above is called Milano's