If you like ancient buildings in rolling wooded hills then Glenalough is your choice.

If you like your rocks w/out the hand of man then the other 2 are your choice.

Bear in mind the Gaint's Causeway is in the North [Pounds vs. Euros]and the general prices probably will be more. What with the rental car premium for crossing the border and all.

Hello - the Burren has quite a few man made monuments - over 2500 historical sites over the last 6000 plus years!

:)

The Poulnabrone dolman is probably the most iconic, blending into the landscape.

burrenbeo.com/…

In my opinion, one of the most beautiful places in Ireland is Glendalough and St. Kevin's monestary. I was there a few years ago with my church choir, and we had the opportunity to give a concert within the ruins of the church. It was something I will never forget. I'm going back this fall with friends, and am insisting we go to Glendalough. Avoca was also one of the most beautiful places around.

I was disappointed inthe Cliff sof Moher, and did not get up to the Giant's causeway, althought that is on for this trip.

You won't be disappointed if you go to Glendalough.

I'd vote for the Burren and surrounding areas.

There's a great deal more to the Burren than just rocks -- start in Kilfenora at the Burren Center, the ruins of the Cathedral, and get a fix of music and dancing, go up to Mullach Mor and explore, drive the coastal road to Kinvara (more music, but on the way, stop on the seacliffs and find yourselves some of the gentians to gaze at) and visit the castle, come back down through Ballyvaughan, visit Poulnabrone and the dig at Caherconnell ( http://www.burrenforts.ie/ ).

Visit the Cascades and dabble your feet in the water at Ennistymon, stop in Lehinch at Seaworld (small but fascinating, with a huge sea tank!) and take a walk along the Promenade (lunch at Looney's, if you can get in, is good), stop at the Rock Shop and St. Brigid's Well on the hill, visit the Cliffs of Moher, then up to Doolin for more music, more stunning rocky beaches, and some lovely food up at the Doolin Cafe up by the church (the craft shop next to it is now, regrettably, closed). Take a trip out the Aran Islands!

Friends of mine have a working farm in the Burren outside Kilfenora, and it fascinates me how the farmers work with the landscape.

How long do you have for your trip?

Agree with KB and Ferdia here.

First impresssions of The Burren region and landscape gives the impression that it is a barren soulless region yet in this easily drivable area you will find many excellent monastic ruins, castles,holy wells,megaliths such as Poul na Bron that was mentioned above and of course the splendid wild flowers that it is famous for.There are also some fantastic walks on "green roads" on many of the mountains!

http://www.burrennationalpark.ie/gallery.html

To truly appreciate the area you really need to get a good local map such as the map of the Burren by Tim Robinson which can be picked up locally.

amazon.co.uk/Burren-Inch-Uplands-North-west-…

or also some of the ramblers guides to the Burren by Tir Eolas.http://www.tireolas.com/ballyvaug_mp.htm

You will find so much more if you are prepared to get out and explore. You won't be disappointed.

Glendalough is wonderful no doubt but an overall trip to the Burren is worth it if you do your research before hand and scratch beneath the surface.

The monastery of Kilmacduagh is just outside the town of Gort,on the edge of The Burren and is well worth a visit and as good as Glendalough.

http://www.stcolman.com/life_monastery.html

and also the lovely abbey of Corcomroe.

irish-architecture.com/buildings_ireland/cla…

Where are you setting out from? Where do you need to be when the trip is done? For example, would this proposed trip be the total trip or part of a bigger trip? Flying in and out of Dublin? Shannon? Belfast? None of the above? Renting a car? Using public transport?

I would recommend the Giant's Causeway. Then you can drive along the beautiful North Coast, and take in all the little villages, go on the rope bridge, visit the Bushmills Distillery, see some beautiful beaches such as the White Rocks outside Portrush.

I only have one day to get out of Dublin (longer trip, but the rest of the time I need to be in town for business).

So, only one day, and probably going with a train/bus tour, rather than taking a car.

yankancuch - I don't think you'll do any justice to the Burren in that timescale, so would opt for either of the others as a day trip from Dublin.

Since you have only time to do this as a day trip I would opt for Glendalough. It seems to me to be the more practical, relaxed day trip from Dublin - a nice break from all the business stuff.