I lived in Shannon for 2 1/2 years.
Forget about Shannon town, it is just a place to work and sleep. Ennis, about 10 miles to the north is very nice, also Limerick is much better than it´s reputation (during the last few years they did a major clean-up, and all the Victorian slums are gone), in Western Ireland I´d advise you to go to the Cliffs of Moher, then the Burren area just south of Galway bay (it is said that the moon like landscape inspired Tolkien to write his Lord of the Rings), Galway is a nice town as well, and if you´ve got time, drive up to Connemarra National Park northwest of Galway.
For aviation enthusiasts, there is Foynes on the south bank of the Shannon estuary, the old 1930s Pan Am flying boat base. The old terminal building is today a museum.
Nothren Tipperary (the area around Nenagh) is very beautifull as well, I don´t know if they opened it already, but the people in Silvermines wanted to convert an old mine in a museum. It has a spectacular manmade cave (I´ve been inside this mine several time potholing before it got opened to the public).
If there are more questions, feel frre to ask.
Je Suis Charlie et je suis Ahmet aussi