Hi Tom, You might want to check out Solas, if you haven't already. Their first three albums are incredible (especially the first one "Solas") and were done when John Doyle and Karen Kasey were still in the band.
Danu's last two albums with their girl singer with the unpronounceable name are also worth checking out.
The first Planxty album is kind of a landmark and I think you can hear it's influence on the Waterboys and maybe The Pogues. Actually all their recordings were quite good. After the Break , especially and their reunion DVD which can also be had as a CD and is priceless.vl