For best practice see here
For worst practice I would suggest a walk around places like Blessington Street, Upper Gardner Street etc;
Other projects of note on the positive side would have to include the Merrion Hotel and 14/15 Stephens Green.
Carton Demense has irked quite a few in the conservation community whilst the City West Hotel and shed complex has really annoyed many.
I am sure many others can add significantly to this list.