Next to the GPO is the Dublin spire built in 2003 to replace the Nelsons column which was blown up by the IRA in the 1960's. It's the highest freestanding sculpture in the world at 120m (i think), its been given a few nicknames by locals, such as "the Spire in the Mire", "the Pointless point" and "the Stiffy by the Liffey"
Cleary's department store, one of the oldest and biggest in Dublin is just opposite the GPO and Spire. Look at those crappy little trees - O'Connell Street used to be lined with mature London Plain trees but a few years ago they were chopped down because they were "too British" (Pathetic)
To the west of town is The Phoenix park, the largest urban park in europe. 5 times the size of London's Hyde park. Within the park is the Residence of Irelands president (built 50 years before America's White house, so they copyed Ireland )