Where would you stay to start your vacation? We plan on a couple of days in Dublin but can't decide on staying in Dublin or in Howth or Don Laoghaire . . .
Howth and Dun Laoghaire are both easily reachable by DART public transit, so it just depends on whether you'd rather be in the city center or an outlying area. If you have a rental car, you might be better off staying out of the center, as parking is expensive in the city (and the traffic is no treat, either).
Stay in Dublin if you can - yes it is easily reached from Don Laoghaire but you will have the travel time to contend with and it is not a very interesting area - or so we found.