DOP: dizionario italiano multimediale e multilingue d'ortografia e di pronunzia. Roma: Rai-ERI, 2010.
When deciding whether to get the new print edition of DOP , I looked it up online and found that the new "multimediale e multilingue" edition has a great suite of online tools. Now, instead of just reading about how to pronounce a word, you can actually hear it!
In addition to detailed phonetic spelling to individual words, you can click on the accompanying little red arrows to listen to the preferred pronunciation. There is also an anthology of 53 selected texts from the 13th-20th centuries that you can listen to while looking at the text. This would be a great teaching tool, in addition to its research value. While I'll still get the newest version for the IC Reference collection, I think that it is well worth knowing about this online resource.