Maybe I missed something here but this seems like a whole lot of nothing to me. I can use Daft and MyHome to have a look at property price data if I'm so inclined. If this register isn't going to publish actual sale prices it's as good as useless in my book. And I haven't seen anything to suggest achieved sale prices will be included.
It'll just run along the lines of the ESRI/PTSB jobby...
IE averages in large areas with little or no break down.
This will really only be capable of giving a broad indicator of prices continuing to drop or prices beginning to stabilise and increase.
Now since the state owns so much property via NAMA... I can't see it being anything but a frigging great time to buy... always.!