Many people stay in Ennis on either their first or last night in Ireland before flying out of Shannon Airport. I stayed my first night in Ennis and, honestly didn't see anything remarkable there. However, I stayed my last two nights in Ennis and only then discovered how lovely it was. The town center is quite charming, the people are lovely and the B&B's in Ennis (there are many) are excellent. You are also close to other fine attractions and castles and the bus conveniently stops in Ennis.
Quick Tips:
There aren't any supermarkets nearby so you'll have to rely on the numerous gas station mini-markets for food.Best Way To Get Around:
Walking is definitely the best way to get around in Ireland. The bus system, Bus Eirann, is excellent, cheap, reliable and easy to follow. There is a bus station in Ennis that is pretty centrally-located.