For Americans (or other North Americans) coming in via Shannon: a short (25 min?) drive into the city from the airport, parking in underground garage that is gated. Very helpful staff that understood I was flat out exhausted but had to stay up for jet lag. I could leave my luggage in my car until the room was ready. Short walk into city center, sites to see, and the river walk. Strongly recommended. Buffet or to-order breakfast was robust, more than enough, and with a nice view of the river. Go ahead and add that. Great base for operations.