Many of the statues of Dublin have been given nicknames by the locals - the ones I knew about are:
Statue of Molly Malone at the foot of Grafton Street - nicknamed the Tart with the Cart
Statue of Anna Livia (personification of the River Liffey as a woman sitting on a slope with water running down past her, bubbling) - nicknamed the Hoor in the Sewer, Viagra Falls or the Floozie in the Jacuzzi. This last nickname is apparently also applied to a fountain cum statue in Victoria Square Birmingham.
Others I have identified ( from http://en.wikipedia.org/wiki/Irish_statues_and_their_nicknames) include:
The Spire of Dublin on O'Connell Street. This was erected (to commemorate the Millennium) in January 2003. It has apparently already received a number of nicknames including the Stiletto in the Ghetto and the North Pole, (O'Connell Street being on the northside of Dublin).
Close to the Spire on North Earl Street is a statue of James Joyce apparently known as the Prick with the Stick.
By the recently restored Ha'penny Bridge over the Liffey is a statue of two women sitting talking on a bench with shopping bags at their feet - known as the Hags with the Bags.
There was also apparently a statue of Queen Victoria (removed in 1947) which was know as the Auld Bitch. This was apparently sold to Sydney in the 1980s.
Statues I haven't found a nickname for include:
The Famine Memorial on Custom House Quay - which is perhaps too harrowing for such levity
The poet Patrick Kavanagh next to the Grand Canal - apparently one of his favourite places.